Click any customers that arrive and then the front desk to start. Then, click the customer and the room number shown or any other area requested. (Some arriving customers will request to go directly to the restaurant or gym without checking into a room.)
When a laundry basket appears outside a door, click it and the laundry room. Then, click the folded laundry and the room where it should be returned. When a vacuum appears above a room, click the cleaning supply room and then the room showing that cleaning request.
Finally, when a customer is ready to leave, you'll see an exit icon. Click the customer and then the main door. Don't make them wait too long!