How to perform OAuth2 with Postman

Following the doc at Postman Echo, I can perform operations such as get, post, oauth1, and so on.

However when performing operation with oauth2’s Request Token. Postman returns Unauthorized.

In the Get New Access Token dialogue, I use following information:

Grant Type: Authorization Code
Callback URL: https://www.getpostman.com/oauth2/callback
Auth URL: https://postman-echo.com/digest-auth
Client ID: abc123
Client Secret: ssh-secret
Client Authentication: Send as Basic Auth header

What other information are needed? Thanks