Hi,
RMP API's can be authenticated using Basic login.
In your API call, add Authorization header, Baisc + base64 encoded string of login:password.
There is no 1st or 2nd API to authenticate.
Also, systematically you can update a process (=advance) from Connector (in library, Validate a manual task).
So a main process can be updated by another process, and this "another process" (who has the connector mentioned above) can be started by timer or email or API call.
Could be useful for some cases.
Best regards,
Taka