iCloud-GarageBand Files

After you log into your iCloud account, you save GarageBand files automatically into your iCloud File Drive.

What Happens with GarageBand Files and iCloud

Tap to launch the GarageBand app. Select the instrument and then create your music!
Tap on the file icon in the top left corner.
Then you will see the most recent GarageBand files. These files are stored in your iCloud Drive. So, if the iPad gets wiped, you can still see these files within the GarageBand app (after logging into your iCloud account).
When you open the Files app, . you should see the GarageBand files there.
So, there’s no restoring files!  You just need to log into your iCloud account on the iPad and you will the GarageBand files within the app.