1. To access the groups, go to Accounts > Groups.
2. On the Groups page, click on Sub Groups for the Group you would like to add your users to.
3. Click on Trainees.
4. This page shows you all of the Trainees currently assigned to this Sub Group. To add a new User/Trainee click on (+) Assign Trainee(s).
5. Select the trainees you would like to assign by checking off the box to the left and click the Assign button when done.