Assigning a tutor gives a classroom access to it. Students then find it in their classroom and can start chatting.
Assigning it
1. Open My Library from the sidebar and click the tutor.
2. Click Assign in the top right.
3. Tick the classrooms you want and confirm.
A tutor can be assigned to as many classrooms as you like. To take it away again, open the same dialog and untick the classroom.