The Group feature in Moodle is pretty handy if you have multiple blocks of a course and/or have two (or more) teachers sharing a course.

Group FAQ's:

1. How to Turn Group Function on:

Turn editing on > Edit Courses Settings >  Groups  >  Group Mode = Visible (or separate)

2.  How to make groups:

Course Admin > Users > Groups > Create Group

3,  How to make an assignment separate per groups:

Turn editing on > Toggle the icon beside your assignment to be "Visible Groups"