From the main screen click on name of your group. (In example: Test)
In the group menu choose Add New Members
Place a check on the box to the left side of the name you wish to add to your group. Then click the green ADD button. *Tip go to bottom of page and expand to larger view as you can only add members 1 page at a time.
If a member is already in the group they will NOT appear on the Current Members list.