Rooms are used to group ago control devices based on their physical location or some other logical grouping. Click on the 'Configuration' button on the left menu then click on 'Rooms' to access the Room Configuration page. Type a name in the text entry box that says 'New room name' and click the 'Create Room' button to create a new room:
The new room is now available and devices can be assigned to the room in device configuration.
Rooms can be edited by clicking the pencil icon to the right of the room name. You can also delete a room by pressing the 'x' button to the far right of the room name.