The results can be filtered by class/group, subgroup or user.
Class/Group
Class/group shows every class you are an administrator for. This is the initial sort level and must be completed for results to appear.
Subgroups
Subgroups show the secondary groups that have been created within a class/group. The users who are in the subgroup will appear in the Users column. To select or unselect a subgroup hold down CMD and click (MAC) or CTRL and click (PC).
Users
User(s) contains the members of a class or subgroup. To select or unselect a user, hold down CMD and click (MAC) or CTRL and click (PC).