Make sure to first have SuperBLT, and BeardLib installed. Click the links in the dependency list.
Optional video tutorial for installing SuperBLT, BeardLib, and mod_overrides mods: https://youtu.be/rin_sjSJIkg
mods
Put "touhouhitsound1.2" folder into PAYDAY 2\mods\saves\ACH Addons\Hitsounds That's it.