Microsoft access help?

i am making a database for a school project and i would like to create a rule by which a tick box in a different table is selected when another table shows that the hotel room is occupied on the current date ie. when the Bookings table shows that a room is occupied on today's date, then the on the room Details table, the Occupied? field (which is a tick box) is selcted. sorry, its kinda confusing :S