The wall with XXIV is the place to begin. Look at the stars on the wall and imagine them as a clock face. If you press the star on the right side of the XXIV wall, you’ll hear one click (after the floor opens slightly) indicating one o’clock (the next star,2 clicks, 2 o’clock, etc). The light shinning is that of the hands of a clock, showing the time: 8:15.