Architecture Scenario: Single Sign-On API


I was reading through the architecture scenarios and wanted to make sure I selected the correct scenario for my use case.

I manage a Discourse app that has its own APIs for the logged in user through a generated token. That Discourse app is connected to Auth0 using SSO. I need to create a mobile app (Ionic) that lets the user authenticate using Auth0 (through in-app browser) using the Discourse Application in order to get a token for him to request the Discourse API and show a customized experience in the app.

I have understood that this qualifies as a Mobile and API architecture, but somehow I get confused on how to consume the Discourse API on behalf of the logged in user.

Any help would be greatly appreciated.