Totally forgot to reply (most likely because it was so late lol), BUT I FIGURED IT OUT! I was trying to copy and paste the whole game folder for the DLC, but I really only needed to move over a single file. The instructions were kind of confusing at first, but I scrolled through some of the other comments here and eventually figured it out :)
Anyways, I may or may not have already played the whole dlc, and it was SO worth the thirty minutes of file explorer HELL (Maybe this is a sign I need to put myself in a computer class??)