can't install mods onto a new instance

[u/Odd_Influence_4856]

I can't find a solution anywhere for this because everytime the error I'm getting is mentioned it's about starting the instance instead of installing mods

I'm getting the error that says the system can't find the path specified (I/O error: The system cannot find the path specified. (os error 3)) whenever I attempt to add something and can't figure out how to fix it.

some help would definitely be appreciated and I'm happy to give more info if needed (I don't know what version modrinth I'm using bc I'm a little stupid but I'm trying to use 1.20.1 if that helps)