- Navigate to Mods/ from the base folder of Monster Girl Dreams, where you found the game executable.
- Extract the .zip file for the mod and place its default mod folder (which contains multiple subfolders) into Mods/
If the subfolders are not immediately after the mod name folder (for example;Mods> MariTheButterfly >MariTheButterfly >Events, Fetishes, Images, etc.) the mod might not work so move the inside folder out(the one that would lead you to the events fetishes images) out to the mods folder
Idk if that makes any sense
For a better explanation you can use the page with the list of mods