Click All Rooms to view the list of My Rooms, Public and Private chat rooms. By clicking on My Rooms, you can view the entire list of private and public rooms that you are a part of. Public rooms are indicated by the unlock icon and private by the lock icon. You can access any room by clicking on the row.
The Public tab lists all of the public rooms that are available at your company. You can view a sample of the chat room and join the room as well. For those that you are a member of, a check icon is present.
If you are an admin, you can access the entire list of private chat rooms available at your company in the Private tab. From here you can access the private rooms that you are a part of.