Did you put the mod folder into a folder of same name by any chance?
Here is how it usually work:
Most modders start the path with the folder "game" inside that folder is all the path folders towards what their mod do.
So all You have to do, is copy the mods folder "game" and go to the game where you see the games "game" folder, and the exe/start game function.
DO NOT CLICK THE GAMES GAME FOLDER!
You click on an EMPTY space and choose "paste"
That way, the folder "game" you just copied, overlaps the games "game" folder and places everything inside into the correct folders, or create those not yet made.
If it ask to overwrite anything, choose YES.
Never paste a folder inside another folder with the same name, thats a rookie mistake, one that mess up everything.
Some modders doesn't use this simple "game" folder start, they just add the closest path to their mod, like "mods->girl"
Then you have to click the game folder and when you see "mods" paste your copied "mods" folder into an empy space, then it overlaps from there.
I can make screen shots if it's still sound complicated?