Here you need to press the white arrow and go to the other part of the room. a potted plant and some candles are placed here. Move the potted plant and you will obtain a matchbox. Light all the candles in the cell. This will illuminate a clue on the ceiling of the cell. The clue shows the order in which the items in the cell need to be counted.
First is Flat books which = 8.
Then Standing books which = 15.
Then Boxes which = 8.
and finally Candles which = 11.
Press the keypad and input 815811 and press OK. Press the white arrow again to go the other side of the room to exit through the hole.
