uhh, i cant describe EXACTLY, but you leave the room (in referenc to the screen) go right, up and around. open the door above the exchange room, then open the next door to get into teh lef tof teh three coupon rooms. By now you have opened two doors, then go into the ventilation system to enter the right of teh three, get the second coupon, then open the third door to get the 3rd coupon. Done.