moving my already external music library from iTunes into Apple Music

I upgraded from High Sierra to Monterey on my iMac, stupidly thinking my iTunes songs and playlists would transfer, which they did in past iTunes upgrades. They did not. My Apple Music is empty.

In preferences, I changed the media location from the hard drive to the external, which has my 45000 song library.

I imported a few songs from a CD and they went into the correct external file, just to check. They do not play when the external drive is disengaged.

How do I get my 45000 songs on the external to be recognized by Apple Music? These are all burned from CDs, nothing downloaded or streamed. It seems I can just drag them a few hundred at a time into Apple Music and that works. Any problem with that? Can they be recognized by Apple Music without "reloading" them all? If so, how?

When I changed the media location of the library in preferences, it asked me weird questions about organizing files and the like, questions I did not know the answer to. But I could not proceed without choosing an option. I didn't want to choose the wrong one and screw up the whole thing.

Why is this so unclear? Is there a way to reach an iTunes/Apple Music expert? In the past, when I've called Apple Help on an iTunes issue, it's a crapshoot if who I get is up on music manipulating. Sometimes they seem confident, sometimes they just don't seem to know.

Should I just manually transfer my 4000 or so artist folders from the external into Apple Music? If that's the safest play, fine with me.

Carl