1. You have to press the skulls in the order shown from the roman numerals on the left side.
I is the top skull, II is the left skull, III is the right skull, and IV is the bottom skull.
2. You can only press the skulls if they are standing upright. It will make a sound and the skull will start moving if you did it correctly.
Holding your phone/device upright, press the top skull.
Now turn it to the right and press the left skull.
From here, flip it upside down completely and press the right skull. Finally, turn it back upright normally and press the bottom skull.
If done correctly, all the skulls will spin and disappear.
Press the window to open it.