Viewing your roster
Your roster is the list of students in each class. From the Classes tab you can open a class to see its members, and from the Students tab you can see everyone across your classes at once.
Removing a student
To remove a student, open the class and choose to remove them from the roster. This stops them from receiving that class's assignments, but their personal account and saved progress stay intact, so they can keep practicing on their own.
Adding students back
You can re-add students any time using the class invite code, or create new accounts. See create a class and create student accounts for the two ways students join.