Hey @isaakskinner For the Authentication Endpoint, it depends on which type of Authentication is configured in the Developer Console Project (here you will have ClientID and Client Secret based on the type of Authentication).
For Analytics, there are two: User Authentication and ServerToServerAuthentication.
For User Authentication, you can refer to: https://developer.adobe.com/developer-console/docs/guides/authentication/UserAuthentication/IMS/
for endpoints.
For ServerToServerAuthentication: https://developer.adobe.com/developer-console/docs/guides/authentication/ServerToServerAuthentication/IMS/ for endpoints.