If you have been invited to a Group, it is important that you accept the invite so that you can begin sharing information. There are two ways to accept the invite.
Notification Bell
The fastest and easiest way to accept an invite is by clicking the notification bell at the top-right of your screen and then clicking View Invite. This will take you to the invitation page where you can choose to Join Group.
Manually Join Group
You can also accept an invite by manually going to the Groups page.
From the profile dropdown in the top right corner, select Admin. Then click Groups in the left hand navigation. Finally, click Join Group.