I personally use the itch app as it's easier on me.
To do this, you have to go to meyaoi games patron page, there will be a couple pages that say sfw2 or sfw4 or something like that; this is the free content. Those are the RPA files and need to go in the game folder. Not for sure if you're a PC or Mac user or whatever.
If you need a more detailed explanation or help, I'm here.