You must catch all the ghosts of each screen, only in this way you can activate the trap that you must collect and activate it to finally enclose them and move on to the next screen. You will find levers that give you access to restricted areas, as well as areas with blades or lava that will make your life a little more difficult. Time is limited on each screen so you don't fall asleep. Once you have caught all the ghosts of the 4 floors of the building you will have completed your mission, good luck!