To follow public Groups:

• In the Feed view, click the plus (+) next to Groups within the left navigation pane. Follow (or, unfollow) any public groups showcased.
  
   

To receive messages from Private Groups, you will need to be added to the group by a member with Admin permissions to update Groups.

To unfollow public Groups:
 

1. Open the Settings menu by clicking on your personal avatar.
    
2. Select Feed Manager.
    
3. Click the unfollow button next to the Group you wish to stop following.

OR

In the Feed view, click the plus (+) next to Groups within the left navigation pane. Follow (or, unfollow) any public groups showcased.