When you first take a look at your Groups, you'll notice that you've got a couple different groups that have been already created for you.

Groups are used to organize your guests into color-coded groups that you can use when the time comes to create your seating chart. 

You can always add, edit, or delete these groups, and also change the colors as you wish. 

Go here to learn more about how to create new groups, or how to edit and delete them from your guest list.