The instructions in the first post are no longer applicable, last updated 2022 but the two people in charge of this project disappeared after that. This is a game unlike any other i've seen that requires a specific version of the game and then a rather complicated installation process with the mod with an external program that integrates it. I put alot of effort than most would into trying to get it to work but ultimately i just ended up finding a recent version of the prepatched game with the mod file on F95 and then using Mtool to translate it.
As i said before the game has an incredible number of issues including wonky hooking of the translation particularly in combat, the sheer size of the mod seems to overwhelm the capabilities of the original game platform which makes it very laggy and unenjoyable.
My suggestion is that you play the base game with mtool first to see if its something you would be able to tolerate, because even without the extra baggage of the mod, the game runs like crap due to it's age and spaghetti code.
Finally i should also note that the dev 'Dreamania' is in the middle of creating Succubus Rhapsodia 2, this time on Unity. That game should have a combat system that is similiar or identical to that of this game without the same kind of engine problems this one does.