Apple Music cannot find any of my music files

Some context:

Until recently, I was using an old MacBook Air on an old operating system, still using iTunes. My music files were stored on an external drive. The motherboard on this machine recently died. I now have a newer MacBook Air, with Ventura OS.

I was able to use Migration Assistant to move all my files and settings from the old hard disc to the new machine. I had also backed up all my music files onto a newer external drive, which has a thunderbolt/USB3 connection.

I had read on this board that you could press Option while opening Music for the first time to import an old iTunes library, and I did this, with apparently no problem. My playlists all appeared on the left-hand column of Music. I also selected the location of the new drive in Settings>Files>Music Media folder location. I clicked Keep Music Media folder organized and Copy files to Music Media folder.

I felt I was all ready to go.

But no. Every single one of my music files has the exclamation point warning.

When I tried to play a track, Music asked me to locate the file. When I proceeded, I could easily navigate to the file location and select the file from its location om my new external drive. I indicated that I wanted Music to use that location to find other missing files. The track played. However, Music was not able to locate any of the other missing files. And I have way too many music files to do this manually for each one.

When I select Get Info on a missing track, it seems the file location where it's looking for the files is not where I have selected (my external drive). Instead, it's looking for in my user music folder.

I don't know why it doesn't know where to look for the files, and I don't know how to change this location for all my files at once. I can't do each track, one file at a time.

Someone please help!

Thanks