I figured out the problem. I thought the fuse for the power seat was already in there, but thanks to my manual I found out it wasn't in there. So I put a fuse in the empty location and the seat worked.

I'm so glad. The only problem is how to secure the backrests of the backseats. The bolts are in, but the backrests don't lock. They can easily be folded down just by barely pulling it.