[Dovecot] Dovecot and Postfix Authentication

[Christopher Trom]

I am a student and am trying to get a mail server setup for a project. I
have all of the Postfix configuration taken care of, but I am confused by
the way that authentication works with Dovecot in the mix. As a user of the
system, am I supposed to authenticate myself to Postfix, Dovecot, both
individually, or both together? My Postfix users are stored in a PostgreSQL
database, should Dovecot also be connected to this db? Some basic pointers
on how this setup ought to look is all that I'm hoping for.

Thank you,
Christopher