Hey @joakim.nilsson
Welcome to the Postman Community! 
If you add this to the Tests of the first request it will store the ShpCSID value as a global variable. I’ve used a global variable here for ease but you could set this at the environment and collection level if you needed too.
pm.globals.set("ShpCSID", pm.response.json().ShpCSID)
In the second request, use { "ShpCSID": {{ShpCSID}} } in place of the hardcoded value.
More information about variables and how to use them can be found here:
https://learning.postman.com/docs/sending-requests/variables/