Joining a group from an invitation:
- Go to your Profile page
- Tap the envelope icon "Invites" button at the top of the page. (If you do not see one, you do not have any invites)
- Tap accept for the group you wish to join.
Requesting to be part of a group:
- Go to the Leaderboard page and select the Groups leaderboard.
- Tap on a group you wish to join.
- Tap on the "Apply To Group" button.
- Wait for your request to be accepted.