There are a number of ways to locate Groups within the site

Access to public groups can be found thru the Connections tab in the main navigation bar.  The main tab for Forums is another way to travel to public groups. 

Your Profile offers access to groups of which you are a member.  Using the arrow in the upper right hand corner next to your name will display a list of group names and icons.  Choosing one will take you to the Group Home page. 

Using the arrow in the upper right hand corner next to your name, choose My Profile.  Groups for which you are a member will display to the right of the menu on the page.  Choosing one will take you to the Group Home page.