Making the holes would be useless because you haven't got any fitting screws + rotary tool. (https://www.amazon.com/Black-Decker-RTX-B-3-Speed-Rotary/dp/B000MUSLCC i heard this one should be good enough but get a secondary cutting disc)
Get a plastic editing tool like a Dremel with a small cutting disc make a cutout for the fan but make it a bit smaller than the fan so that you can use the screwholes of the fan.
Only thing drive me crazy is all these new horror games nowadays is its so dark, all time. I can't even play them. I understand they trying to create spooky but be creative a little, not just darkness with pop out scare scenes.