GarageBand AND MUSIC FILES lost in upgrade of Macbook Pro
I had GarageBand on my late-2011 Macbook Pro, and SLIGHTLY upgraded to a 2012 Macbook Pro with SSD and Catalina. Now my GarageBand has disappeared, and it's not in the App Store under purchases. I have a LOT of files in GarageBand that I suddenly can't access. When I try to "GET" it from the App Store it says my OSX is too LOW! I need 11. But this machine is not capable of that.
Where are my files, and how can I recover my music and put Garage Band on my new machine?
Thanks for any help!
MacBook Pro 13″, macOS 10.15