Number of orders in the response body

Hello. I have a response body with a list of all orders. I need to write a test that will show me the sum of all orders in the same body. maybe someone

{
    "Items": [
        {
            "OrderID": 625879,
            "CompanyID": 490142,
            "OrderPDF": {
                "FileID": "9af78924-8b4c-47c9-bcea-f0b043aae33d"
            },
            "OrderNumber": "202335",
            "CounterParty": {
                "PartyID": 490385,
                "Addresses": [],
                "Street": "Stiftsbergstrasse",
                "StreetNumber": "1",
                "Zipcode": "74172",
                "City": "Neckarsulm",
                "CountryCode": "BE",
                "VATNumber": "BE0451881923",
                "PartyType": "Customer",
                "VATLiable": true,
                "DisplayName": "LIDL BELGIUM GmbH und Co.KG",
                "VATDeductable": true,
                "Identifiers": []
            },
            "OrderDate": "2023-05-14T00:00:00",
            "ExpiryDate": "2023-06-13T00:00:00",
            "OrderType": "Invoice",
            "LastModified": "2023-05-14T12:47:08.053",
            "Created": "2023-05-14T12:47:07.24",
            "OrderDirection": "Income",
            "TotalExcl": 0.00,
            "TotalIncl": 0.00,
            "TotalVAT": 0.00,
            "PaymentReference": "+++202/3351/33915+++",
            "Paid": true,
            "PaidDate": "2023-05-15T00:00:00",
            "Currency": "EUR",
            "IsSent": false,
            "Invoiced": false,
            "RemindersSent": 0,
            "ToPay": 0.00,
            "OrderStatus": "Paid",
            "Overdue": false,
            "FXRateToForeign": 1.00000,
            "ExportedToConnector": false
        },
        {
            "OrderID": 625881,
            "CompanyID": 490142,
            "OrderPDF": {
                "FileID": "e3b70133-8205-4984-90c9-88d39e9baa14"
            },
            "OrderNumber": "202336",
            "CounterParty": {
                "PartyID": 490385,
                "Addresses": [],
                "Street": "Stiftsbergstrasse",
                "StreetNumber": "1",
                "Zipcode": "74172",
                "City": "Neckarsulm",
                "CountryCode": "BE",
                "VATNumber": "BE0451881923",
                "PartyType": "Customer",
                "VATLiable": true,
                "DisplayName": "LIDL BELGIUM GmbH und Co.KG",
                "VATDeductable": true,
                "Identifiers": []
            },
            "OrderDate": "2023-05-14T00:00:00",
            "ExpiryDate": "2023-06-13T00:00:00",
            "OrderType": "Invoice",
            "LastModified": "2023-05-14T12:47:51.277",
            "Created": "2023-05-14T12:47:51.167",
            "OrderDirection": "Income",
            "TotalExcl": 0.00,
            "TotalIncl": 0.00,
            "TotalVAT": 0.00,
            "PaymentReference": "+++202/3361/36752+++",
            "Paid": true,
            "PaidDate": "2023-05-15T00:00:00",
            "Currency": "EUR",
            "IsSent": false,
            "Invoiced": false,
            "RemindersSent": 0,
            "ToPay": 0.00,
            "OrderStatus": "Paid",
            "Overdue": false,
            "FXRateToForeign": 1.00000,
            "ExportedToConnector": false
        },
        {
            "OrderID": 625738,
            "CompanyID": 490142,
            "OrderPDF": {
                "FileID": "460e9e82-627c-43ad-b1fa-ae5f925e4e38"
            },
            "OrderNumber": "202303",
            "CounterParty": {
                "PartyID": 490170,
                "Addresses": [],
                "Street": "Industrielaan",
                "StreetNumber": "125",
                "Zipcode": "1070",
                "City": "Anderlecht",
                "CountryCode": "BE",
                "VATNumber": "BE0505612993",
                "PartyType": "Customer",
                "VATLiable": true,
                "DisplayName": "BMW ANDERLECHT",
                "VATDeductable": true,
                "Identifiers": []
            },
            "OrderDate": "2023-05-12T00:00:00",
            "ExpiryDate": "2023-06-11T00:00:00",
            "OrderType": "Invoice",
            "LastModified": "2023-05-12T19:02:01.96",
            "Created": "2023-05-12T19:02:01.663",
            "OrderDirection": "Income",
            "TotalExcl": 2000.00,
            "TotalIncl": 2000.00,
            "TotalVAT": 0.00,
            "PaymentReference": "+++202/3034/42601+++",
            "Paid": true,
            "PaidDate": "2023-05-15T00:00:00",
            "Currency": "EUR",
            "IsSent": false,
            "Invoiced": false,
            "RemindersSent": 0,
            "ToPay": 0.00,
            "OrderStatus": "Paid",
            "Overdue": false,
            "FXRateToForeign": 1.00000,
            "ExportedToConnector": false
        },
        {
            "OrderID": 625741,
            "CompanyID": 490142,
            "OrderPDF": {
                "FileID": "6de8d8a2-e8e6-46b5-a6c7-1487320777ad"
            },
            "OrderNumber": "202304",
            "CounterParty": {
                "PartyID": 490170,
                "Addresses": [],
                "Street": "Industrielaan",
                "StreetNumber": "125",
                "Zipcode": "1070",
                "City": "Anderlecht",
                "CountryCode": "BE",
                "VATNumber": "BE0505612993",
                "PartyType": "Customer",
                "VATLiable": true,
                "DisplayName": "BMW ANDERLECHT",
                "VATDeductable": true,
                "Identifiers": []
            },
            "OrderDate": "2023-05-12T00:00:00",
            "ExpiryDate": "2023-06-11T00:00:00",
            "OrderType": "Invoice",
            "LastModified": "2023-05-12T19:31:55.293",
            "Created": "2023-05-12T19:31:55.183",
            "OrderDirection": "Income",
            "TotalExcl": 2000.00,
            "TotalIncl": 2000.00,
            "TotalVAT": 0.00,
            "PaymentReference": "+++202/3045/65474+++",
            "Paid": true,
            "PaidDate": "2023-05-15T00:00:00",
            "Currency": "EUR",
            "IsSent": false,
            "Invoiced": false,
            "RemindersSent": 0,
            "ToPay": 0.00,
            "OrderStatus": "Paid",
            "Overdue": false,
            "FXRateToForeign": 1.00000,
            "ExportedToConnector": false
        },
        {
            "OrderID": 625743,
            "CompanyID": 490142,
            "OrderPDF": {
                "FileID": "fa199e95-ddc3-43f3-b5cb-b7328f5608bc"
            },
            "OrderNumber": "202305",
            "CounterParty": {
                "PartyID": 490170,
                "Addresses": [],
                "Street": "Industrielaan",
                "StreetNumber": "125",
                "Zipcode": "1070",
                "City": "Anderlecht",
                "CountryCode": "BE",
                "VATNumber": "BE0505612993",
                "PartyType": "Customer",
                "VATLiable": true,
                "DisplayName": "BMW ANDERLECHT",
                "VATDeductable": true,
                "Identifiers": []
            },
            "OrderDate": "2023-05-12T00:00:00",
            "ExpiryDate": "2023-06-11T00:00:00",
            "OrderType": "Invoice",
            "LastModified": "2023-05-12T19:46:18.163",
            "Created": "2023-05-12T19:46:17.99",
            "OrderDirection": "Income",
            "TotalExcl": 2000.00,
            "TotalIncl": 2000.00,
            "TotalVAT": 0.00,
            "PaymentReference": "+++202/3056/47127+++",
            "Paid": true,
            "PaidDate": "2023-05-15T00:00:00",
            "Currency": "EUR",
            "IsSent": false,
            "Invoiced": false,
            "RemindersSent": 0,
            "ToPay": 0.00,
            "OrderStatus": "Paid",
            "Overdue": false,
            "FXRateToForeign": 1.00000,
            "ExportedToConnector": false
        },
        {
            "OrderID": 625744,
            "CompanyID": 490142,
            "OrderPDF": {
                "FileID": "bcce29bd-0e90-48bc-bd68-76e1f6113f6b"
            },
            "OrderNumber": "202306",
            "CounterParty": {
                "PartyID": 490170,
                "Addresses": [],
                "Street": "Industrielaan",
                "StreetNumber": "125",
                "Zipcode": "1070",
                "City": "Anderlecht",
                "CountryCode": "BE",
                "VATNumber": "BE0505612993",
                "PartyType": "Customer",
                "VATLiable": true,
                "DisplayName": "BMW ANDERLECHT",
                "VATDeductable": true,
                "Identifiers": []
            },
            "OrderDate": "2023-05-12T00:00:00",
            "ExpiryDate": "2023-06-11T00:00:00",
            "OrderType": "Invoice",
            "LastModified": "2023-05-12T19:49:06.887",
            "Created": "2023-05-12T19:49:06.777",
            "OrderDirection": "Income",
            "TotalExcl": 2000.00,
            "TotalIncl": 2000.00,
            "TotalVAT": 0.00,
            "PaymentReference": "+++202/3067/77074+++",
            "Paid": true,
            "PaidDate": "2023-05-15T00:00:00",
            "Currency": "EUR",
            "IsSent": false,
            "Invoiced": false,
            "RemindersSent": 0,
            "ToPay": 0.00,
            "OrderStatus": "Paid",
            "Overdue": false,
            "FXRateToForeign": 1.00000,
            "ExportedToConnector": false
        },
        {
            "OrderID": 625745,
            "CompanyID": 490142,
            "OrderPDF": {
                "FileID": "deb48177-ecd9-48bd-a072-469fe76a4a4c"
            },
            "OrderNumber": "202307",
            "CounterParty": {
                "PartyID": 490170,
                "Addresses": [],
                "Street": "Industrielaan",
                "StreetNumber": "125",
                "Zipcode": "1070",
                "City": "Anderlecht",
                "CountryCode": "BE",
                "VATNumber": "BE0505612993",
                "PartyType": "Customer",
                "VATLiable": true,
                "DisplayName": "BMW ANDERLECHT",
                "VATDeductable": true,
                "Identifiers": []
            },
            "OrderDate": "2023-05-12T00:00:00",
            "ExpiryDate": "2023-06-11T00:00:00",
            "OrderType": "Invoice",
            "LastModified": "2023-05-12T19:49:27.79",
            "Created": "2023-05-12T19:49:27.617",
            "OrderDirection": "Income",
            "TotalExcl": 200.00,
            "TotalIncl": 200.00,
            "TotalVAT": 0.00,
            "PaymentReference": "+++202/3079/56737+++",
            "Paid": true,
            "PaidDate": "2023-05-15T00:00:00",
            "Currency": "EUR",
            "IsSent": false,
            "Invoiced": false,
            "RemindersSent": 0,
            "ToPay": 0.00,
            "OrderStatus": "Paid",
            "Overdue": false,
            "FXRateToForeign": 1.00000,
            "ExportedToConnector": false
        },
        {
            "OrderID": 625746,
            "CompanyID": 490142,
            "OrderPDF": {
                "FileID": "72411deb-568c-44c0-9d31-1aa2b1f277d9"
            },
            "OrderNumber": "202308",
            "CounterParty": {
                "PartyID": 490170,
                "Addresses": [],
                "Street": "Industrielaan",
                "StreetNumber": "125",
                "Zipcode": "1070",
                "City": "Anderlecht",
                "CountryCode": "BE",
                "VATNumber": "BE0505612993",
                "PartyType": "Customer",
                "VATLiable": true,
                "DisplayName": "BMW ANDERLECHT",
                "VATDeductable": true,
                "Identifiers": []
            },
            "OrderDate": "2023-05-12T00:00:00",
            "ExpiryDate": "2023-06-11T00:00:00",
            "OrderType": "Invoice",
            "LastModified": "2023-05-12T20:00:16.187",
            "Created": "2023-05-12T20:00:16.017",
            "OrderDirection": "Income",
            "TotalExcl": 2000.00,
            "TotalIncl": 2000.00,
            "TotalVAT": 0.00,
            "PaymentReference": "+++202/3080/51313+++",
            "Paid": true,
            "PaidDate": "2023-05-15T00:00:00",
            "Currency": "EUR",
            "IsSent": false,
            "Invoiced": false,
            "RemindersSent": 0,
            "ToPay": 0.00,
            "OrderStatus": "Paid",
            "Overdue": false,
            "FXRateToForeign": 1.00000,
            "ExportedToConnector": false
        },
        {
            "OrderID": 625747,
            "CompanyID": 490142,
            "OrderPDF": {
                "FileID": "9433e876-d769-4ff2-834b-719a4fa01ecd"
            },
            "OrderNumber": "202309",
            "CounterParty": {
                "PartyID": 490170,
                "Addresses": [],
                "Street": "Industrielaan",
                "StreetNumber": "125",
                "Zipcode": "1070",
                "City": "Anderlecht",
                "CountryCode": "BE",
                "VATNumber": "BE0505612993",
                "PartyType": "Customer",
                "VATLiable": true,
                "DisplayName": "BMW ANDERLECHT",
                "VATDeductable": true,
                "Identifiers": []
            },
            "OrderDate": "2023-05-12T00:00:00",
            "ExpiryDate": "2023-06-11T00:00:00",
            "OrderType": "Invoice",
            "LastModified": "2023-05-12T20:00:35.743",
            "Created": "2023-05-12T20:00:35.6",
            "OrderDirection": "Income",
            "TotalExcl": 200.00,
            "TotalIncl": 200.00,
            "TotalVAT": 0.00,
            "PaymentReference": "+++202/3091/00125+++",
            "Paid": true,
            "PaidDate": "2023-05-15T00:00:00",
            "Currency": "EUR",
            "IsSent": false,
            "Invoiced": false,
            "RemindersSent": 0,
            "ToPay": 0.00,
            "OrderStatus": "Paid",
            "Overdue": false,
            "FXRateToForeign": 1.00000,
            "ExportedToConnector": false
        },
        {
            "OrderID": 625748,
            "CompanyID": 490142,
            "OrderPDF": {
                "FileID": "66beb9fc-550d-442b-b31f-d4a0876512cd"
            },
            "OrderNumber": "202310",
            "CounterParty": {
                "PartyID": 490170,
                "Addresses": [],
                "Street": "Industrielaan",
                "StreetNumber": "125",
                "Zipcode": "1070",
                "City": "Anderlecht",
                "CountryCode": "BE",
                "VATNumber": "BE0505612993",
                "PartyType": "Customer",
                "VATLiable": true,
                "DisplayName": "BMW ANDERLECHT",
                "VATDeductable": true,
                "Identifiers": []
            },
            "OrderDate": "2023-05-12T00:00:00",
            "ExpiryDate": "2023-06-11T00:00:00",
            "OrderType": "Invoice",
            "LastModified": "2023-05-12T20:09:26.613",
            "Created": "2023-05-12T20:09:26.473",
            "OrderDirection": "Income",
            "TotalExcl": 2000.00,
            "TotalIncl": 2000.00,
            "TotalVAT": 0.00,
            "PaymentReference": "+++202/3106/47677+++",
            "Paid": true,
            "PaidDate": "2023-05-15T00:00:00",
            "Currency": "EUR",
            "IsSent": false,
            "Invoiced": false,
            "RemindersSent": 0,
            "ToPay": 0.00,
            "OrderStatus": "Paid",
            "Overdue": false,
            "FXRateToForeign": 1.00000,
            "ExportedToConnector": false
        },
        {
            "OrderID": 625749,
            "CompanyID": 490142,
            "OrderPDF": {
                "FileID": "e7ea535e-75cd-4ea8-abc5-e70a0b1db53a"
            },
            "OrderNumber": "202311",
            "CounterParty": {
                "PartyID": 490170,
                "Addresses": [],
                "Street": "Industrielaan",
                "StreetNumber": "125",
                "Zipcode": "1070",
                "City": "Anderlecht",
                "CountryCode": "BE",
                "VATNumber": "BE0505612993",
                "PartyType": "Customer",
                "VATLiable": true,
                "DisplayName": "BMW ANDERLECHT",
                "VATDeductable": true,
                "Identifiers": []
            },
            "OrderDate": "2023-05-12T00:00:00",
            "ExpiryDate": "2023-06-11T00:00:00",
            "OrderType": "Invoice",
            "LastModified": "2023-05-12T20:09:47.167",
            "Created": "2023-05-12T20:09:46.977",
            "OrderDirection": "Income",
            "TotalExcl": 200.00,
            "TotalIncl": 200.00,
            "TotalVAT": 0.00,
            "PaymentReference": "+++202/3113/56080+++",
            "Paid": true,
            "PaidDate": "2023-05-15T00:00:00",
            "Currency": "EUR",
            "IsSent": false,
            "Invoiced": false,
            "RemindersSent": 0,
            "ToPay": 0.00,
            "OrderStatus": "Paid",
            "Overdue": false,
            "FXRateToForeign": 1.00000,
            "ExportedToConnector": false
        },
        {
            "OrderID": 625750,
            "CompanyID": 490142,
            "OrderPDF": {
                "FileID": "bfe7ca36-d3dc-44ed-bb0b-ffd91cc83026"
            },
            "OrderNumber": "202312",
            "CounterParty": {
                "PartyID": 490170,
                "Addresses": [],
                "Street": "Industrielaan",
                "StreetNumber": "125",
                "Zipcode": "1070",
                "City": "Anderlecht",
                "CountryCode": "BE",
                "VATNumber": "BE0505612993",
                "PartyType": "Customer",
                "VATLiable": true,
                "DisplayName": "BMW ANDERLECHT",
                "VATDeductable": true,
                "Identifiers": []
            },
            "OrderDate": "2023-05-12T00:00:00",
            "ExpiryDate": "2023-06-11T00:00:00",
            "OrderType": "Invoice",
            "LastModified": "2023-05-12T20:11:05.683",
            "Created": "2023-05-12T20:11:04.917",
            "OrderDirection": "Income",
            "TotalExcl": 2000.00,
            "TotalIncl": 2000.00,
            "TotalVAT": 0.00,
            "PaymentReference": "+++202/3121/86543+++",
            "Paid": true,
            "PaidDate": "2023-05-15T00:00:00",
            "Currency": "EUR",
            "IsSent": false,
            "Invoiced": false,
            "RemindersSent": 0,
            "ToPay": 0.00,
            "OrderStatus": "Paid",
            "Overdue": false,
            "FXRateToForeign": 1.00000,
            "ExportedToConnector": false
        },
        {
            "OrderID": 625751,
            "CompanyID": 490142,
            "OrderPDF": {
                "FileID": "97ff2a39-7c7c-4ffa-8c99-35c6381e3625"
            },
            "OrderNumber": "202313",
            "CounterParty": {
                "PartyID": 490170,
                "Addresses": [],
                "Street": "Industrielaan",
                "StreetNumber": "125",
                "Zipcode": "1070",
                "City": "Anderlecht",
                "CountryCode": "BE",
                "VATNumber": "BE0505612993",
                "PartyType": "Customer",
                "VATLiable": true,
                "DisplayName": "BMW ANDERLECHT",
                "VATDeductable": true,
                "Identifiers": []
            },
            "OrderDate": "2023-05-12T00:00:00",
            "ExpiryDate": "2023-06-11T00:00:00",
            "OrderType": "Invoice",
            "LastModified": "2023-05-12T20:11:26.59",
            "Created": "2023-05-12T20:11:26.45",
            "OrderDirection": "Income",
            "TotalExcl": 200.00,
            "TotalIncl": 200.00,
            "TotalVAT": 0.00,
            "PaymentReference": "+++202/3138/38169+++",
            "Paid": true,
            "PaidDate": "2023-05-15T00:00:00",
            "Currency": "EUR",
            "IsSent": false,
            "Invoiced": false,
            "RemindersSent": 0,
            "ToPay": 0.00,
            "OrderStatus": "Paid",
            "Overdue": false,
            "FXRateToForeign": 1.00000,
            "ExportedToConnector": false
        },
        {
            "OrderID": 625752,
            "CompanyID": 490142,
            "OrderPDF": {
                "FileID": "ce54e3a8-b4e2-4713-befd-a85c216fe080"
            },
            "OrderNumber": "202314",
            "CounterParty": {
                "PartyID": 490170,
                "Addresses": [],
                "Street": "Industrielaan",
                "StreetNumber": "125",
                "Zipcode": "1070",
                "City": "Anderlecht",
                "CountryCode": "BE",
                "VATNumber": "BE0505612993",
                "PartyType": "Customer",
                "VATLiable": true,
                "DisplayName": "BMW ANDERLECHT",
                "VATDeductable": true,
                "Identifiers": []
            },
            "OrderDate": "2023-05-12T00:00:00",
            "ExpiryDate": "2023-06-11T00:00:00",
            "OrderType": "Invoice",
            "LastModified": "2023-05-12T20:12:10.4",
            "Created": "2023-05-12T20:12:10.243",
            "OrderDirection": "Income",
            "TotalExcl": 2000.00,
            "TotalIncl": 2000.00,
            "TotalVAT": 0.00,
            "PaymentReference": "+++202/3143/08722+++",
            "Paid": true,
            "PaidDate": "2023-05-15T00:00:00",
            "Currency": "EUR",
            "IsSent": false,
            "Invoiced": false,
            "RemindersSent": 0,
            "ToPay": 0.00,
            "OrderStatus": "Paid",
            "Overdue": false,
            "FXRateToForeign": 1.00000,
            "ExportedToConnector": false
        },
        {
            "OrderID": 625753,
            "CompanyID": 490142,
            "OrderPDF": {
                "FileID": "b1dced3d-7eca-4ba4-9af2-318dffc7f06b"
            },
            "OrderNumber": "202315",
            "CounterParty": {
                "PartyID": 490170,
                "Addresses": [],
                "Street": "Industrielaan",
                "StreetNumber": "125",
                "Zipcode": "1070",
                "City": "Anderlecht",
                "CountryCode": "BE",
                "VATNumber": "BE0505612993",
                "PartyType": "Customer",
                "VATLiable": true,
                "DisplayName": "BMW ANDERLECHT",
                "VATDeductable": true,
                "Identifiers": []
            },
            "OrderDate": "2023-05-12T00:00:00",
            "ExpiryDate": "2023-06-11T00:00:00",
            "OrderType": "Invoice",
            "LastModified": "2023-05-12T20:12:28.477",
            "Created": "2023-05-12T20:12:28.367",
            "OrderDirection": "Income",
            "TotalExcl": 2000.00,
            "TotalIncl": 2000.00,
            "TotalVAT": 0.00,
            "PaymentReference": "+++202/3159/65196+++",
            "Paid": true,
            "PaidDate": "2023-05-15T00:00:00",
            "Currency": "EUR",
            "IsSent": false,
            "Invoiced": false,
            "RemindersSent": 0,
            "ToPay": 0.00,
            "OrderStatus": "Paid",
            "Overdue": false,
            "FXRateToForeign": 1.00000,
            "ExportedToConnector": false
        },
        {
            "OrderID": 625755,
            "CompanyID": 490142,
            "OrderPDF": {
                "FileID": "04cd19b3-5969-4428-8c6c-47c6b1643ef9"
            },
            "OrderNumber": "202316",
            "CounterParty": {
                "PartyID": 490170,
                "Addresses": [],
                "Street": "Industrielaan",
                "StreetNumber": "125",
                "Zipcode": "1070",
                "City": "Anderlecht",
                "CountryCode": "BE",
                "VATNumber": "BE0505612993",
                "PartyType": "Customer",
                "VATLiable": true,
                "DisplayName": "BMW ANDERLECHT",
                "VATDeductable": true,
                "Identifiers": []
            },
            "OrderDate": "2023-05-12T00:00:00",
            "ExpiryDate": "2023-06-11T00:00:00",
            "OrderType": "Invoice",
            "LastModified": "2023-05-12T20:20:46.327",
            "Created": "2023-05-12T20:20:46.17",
            "OrderDirection": "Income",
            "TotalExcl": 2000.00,
            "TotalIncl": 2000.00,
            "TotalVAT": 0.00,
            "PaymentReference": "+++202/3165/95801+++",
            "Paid": true,
            "PaidDate": "2023-05-15T00:00:00",
            "Currency": "EUR",
            "IsSent": false,
            "Invoiced": false,
            "RemindersSent": 0,
            "ToPay": 0.00,
            "OrderStatus": "Paid",
            "Overdue": false,
            "FXRateToForeign": 1.00000,
            "ExportedToConnector": false
        },
        {
            "OrderID": 625756,
            "CompanyID": 490142,
            "OrderPDF": {
                "FileID": "b61b2fae-7830-451d-a703-f6e0196a0bef"
            },
            "OrderNumber": "202317",
            "CounterParty": {
                "PartyID": 490170,
                "Addresses": [],
                "Street": "Industrielaan",
                "StreetNumber": "125",
                "Zipcode": "1070",
                "City": "Anderlecht",
                "CountryCode": "BE",
                "VATNumber": "BE0505612993",
                "PartyType": "Customer",
                "VATLiable": true,
                "DisplayName": "BMW ANDERLECHT",
                "VATDeductable": true,
                "Identifiers": []
            },
            "OrderDate": "2023-05-12T00:00:00",
            "ExpiryDate": "2023-06-11T00:00:00",
            "OrderType": "Invoice",
            "LastModified": "2023-05-12T20:24:53.357",
            "Created": "2023-05-12T20:24:52.983",
            "OrderDirection": "Income",
            "TotalExcl": 2000.00,
            "TotalIncl": 2000.00,
            "TotalVAT": 0.00,
            "PaymentReference": "+++202/3173/48862+++",
            "Paid": true,
            "PaidDate": "2023-05-15T00:00:00",
            "Currency": "EUR",
            "IsSent": false,
            "Invoiced": false,
            "RemindersSent": 0,
            "ToPay": 0.00,
            "OrderStatus": "Paid",
            "Overdue": false,
            "FXRateToForeign": 1.00000,
            "ExportedToConnector": false
        },
        {
            "OrderID": 625757,
            "CompanyID": 490142,
            "OrderPDF": {
                "FileID": "c0a44a0f-e7b2-42a0-8ed4-5091825640e5"
            },
            "OrderNumber": "202318",
            "CounterParty": {
                "PartyID": 490170,
                "Addresses": [],
                "Street": "Industrielaan",
                "StreetNumber": "125",
                "Zipcode": "1070",
                "City": "Anderlecht",
                "CountryCode": "BE",
                "VATNumber": "BE0505612993",
                "PartyType": "Customer",
                "VATLiable": true,
                "DisplayName": "BMW ANDERLECHT",
                "VATDeductable": true,
                "Identifiers": []
            },
            "OrderDate": "2023-05-12T00:00:00",
            "ExpiryDate": "2023-06-11T00:00:00",
            "OrderType": "Invoice",
            "LastModified": "2023-05-12T20:25:36.617",
            "Created": "2023-05-12T20:25:36.507",
            "OrderDirection": "Income",
            "TotalExcl": 2000.00,
            "TotalIncl": 2000.00,
            "TotalVAT": 0.00,
            "PaymentReference": "+++202/3180/44939+++",
            "Paid": true,
            "PaidDate": "2023-05-15T00:00:00",
            "Currency": "EUR",
            "IsSent": false,
            "Invoiced": false,
            "RemindersSent": 0,
            "ToPay": 0.00,
            "OrderStatus": "Paid",
            "Overdue": false,
            "FXRateToForeign": 1.00000,
            "ExportedToConnector": false
        },
        {
            "OrderID": 625758,
            "CompanyID": 490142,
            "OrderPDF": {
                "FileID": "0facb886-f3be-4900-a6b1-67edb6a7cef9"
            },
            "OrderNumber": "202319",
            "CounterParty": {
                "PartyID": 490170,
                "Addresses": [],
                "Street": "Industrielaan",
                "StreetNumber": "125",
                "Zipcode": "1070",
                "City": "Anderlecht",
                "CountryCode": "BE",
                "VATNumber": "BE0505612993",
                "PartyType": "Customer",
                "VATLiable": true,
                "DisplayName": "BMW ANDERLECHT",
                "VATDeductable": true,
                "Identifiers": []
            },
            "OrderDate": "2023-05-12T00:00:00",
            "ExpiryDate": "2023-06-11T00:00:00",
            "OrderType": "Invoice",
            "LastModified": "2023-05-12T20:29:01.203",
            "Created": "2023-05-12T20:29:01.063",
            "OrderDirection": "Income",
            "TotalExcl": 2000.00,
            "TotalIncl": 2000.00,
            "TotalVAT": 0.00,
            "PaymentReference": "+++202/3193/48274+++",
            "Paid": true,
            "PaidDate": "2023-05-15T00:00:00",
            "Currency": "EUR",
            "IsSent": false,
            "Invoiced": false,
            "RemindersSent": 0,
            "ToPay": 0.00,
            "OrderStatus": "Paid",
            "Overdue": false,
            "FXRateToForeign": 1.00000,
            "ExportedToConnector": false
        },
        {
            "OrderID": 625759,
            "CompanyID": 490142,
            "OrderPDF": {
                "FileID": "142d6cc0-5001-44ec-b611-9ef741d1b879"
            },
            "OrderNumber": "202320",
            "CounterParty": {
                "PartyID": 490170,
                "Addresses": [],
                "Street": "Industrielaan",
                "StreetNumber": "125",
                "Zipcode": "1070",
                "City": "Anderlecht",
                "CountryCode": "BE",
                "VATNumber": "BE0505612993",
                "PartyType": "Customer",
                "VATLiable": true,
                "DisplayName": "BMW ANDERLECHT",
                "VATDeductable": true,
                "Identifiers": []
            },
            "OrderDate": "2023-05-12T00:00:00",
            "ExpiryDate": "2023-06-11T00:00:00",
            "OrderType": "Invoice",
            "LastModified": "2023-05-12T20:29:56.457",
            "Created": "2023-05-12T20:29:56.3",
            "OrderDirection": "Income",
            "TotalExcl": 2000.00,
            "TotalIncl": 2000.00,
            "TotalVAT": 0.00,
            "PaymentReference": "+++202/3200/35156+++",
            "Paid": true,
            "PaidDate": "2023-05-15T00:00:00",
            "Currency": "EUR",
            "IsSent": false,
            "Invoiced": false,
            "RemindersSent": 0,
            "ToPay": 0.00,
            "OrderStatus": "Paid",
            "Overdue": false,
            "FXRateToForeign": 1.00000,
            "ExportedToConnector": false
    
}
    ]
}

Do you mean the count of orders\objects in the “items” array?

As items is an array, you can use the array.length function to tell you how many objects are being returned.

Something similar to the following (replace xx with the number you are expecting).

const response = pm.response.json();
let noOfItems = response.Items.length
console.log(noOfItems);

pm.test(`number of items = xx`, function(){   
    pm.expect(noIfItems).to.eql(xx)      
})