If you need to remove a user from a specific group, you can quickly do so by following the steps below:
1. Click Actions on the right hand side of their profile and then Edit Groups.
2. Click the box to the left of the group(s) you wish to remove the user from (so that the check mark is removed)
3. Next, click Save Changes
For information on how to create and edit groups, and add users to them, please click here.