C:\Program Files (x86)\Steam\steamapps\common\The Binding of Isaac Rebirth\resources

If it's not here, because you don't see a 'Steam' folder, it means that you relocated your steam directories somewhere else. If that's the case, I have no idea where it would be.

fuck.

If you are still looking for it: Right-click on rebirth in steam, click properties, local files, explore local files. (Exit out of big picture mode before that if you have it enabled) This will open a explorer window in which you can open the resources folder.

in libray?

i dont see local files

I made a picture for you: https://moddingofisaac.com/client/Untitled.png

it came up with nothing.

WAIT! HOW DO I PUT MY MODS IN THE FOLDER? IT CLOSES OUT
WHEN I GO FOR THR MODS

Unfortunately I can't teach you how to use a computer, please consult a local computer expert / store on that matter, google may also help. Once this is done and you still have actual questions about modding The Binding of Isaac, please create a new thread in this forum.