Download the hack that you want to use.
Download an injector like this one: https://www.mpgh.net/forum/showthread.php?t=832475
Start it as admin.
Enter GRP.exe as process name(I'm not sure if this is the correct one, tho).
Press "Add DLL" and find the hack.
Press Inject.
And yeah, you might have to disable DEP(Data Execution Prevention-because your game might crash)