All public rooms work in a similar way.
You can walk around the room by clicking on the tile on the floor where you want to end up. If you want to sit on a chair, click on the tile under the chair. To get a drink, click on a tile at the counter and wait for your waitress, Maria, to come to you. If you're close to someone, select 'say'. If you're further away, they won't hear you, so choose 'shout'.