How to call REST API using SSO?

Summary:

We have SSO enabled in our CPQ. Using IDCS as the IDP.

Now we're trying to make some REST calls, but we're not able to do it, because users are only SSO, and then we get the error "User must login via Single Sign-On"

I saw in some document from support, that we could pass the sessionId in the url, but I could not find how to authenticate and get the sessionId.

Any thoughts?

Response (using Postman)

Version (include the version you are using, if applicable):

24D