TV app not accessing external hard drive for movie files

I just got an iMac, and have Big Sur 11.5.2.

Just getting things set up and I have an issue with the TV app. I changed the library file location to access my external hard drive (which shows up and can be accessed just fine thru Finder) But none of my movies are showing up thru TV on the computer , and are not accessed by my Apple TV either. It's the same with my music files as well.

The only movies/ shows that DO show up are those I purchased thru iTunes Store, and I assume that's because they are attached to my iTunes account.

Any ideas on how to fix this?

Thanks