Garageband Official Apple Support
Hotlinks on Official Apple GarageBand site do not work?
But then these do not work:
You get:
Please advise me.
Thank you,
Computatrum
MacBook Pro 15", macOS 10.15
You are looking at a webpage for GarageBand iOS - for the iPhone or iPad version of GarageBand; the download links for the sound library will only work, when you access them on a device, that is compatible with mobile version of GarageBand. And the site is no longer current anyway. It has been written for the version 2.3 on iOS 11. The current, supported version of GarageBand iOS for your mobile devices is version 4.1 (GarageBand on the App Store) for iOS 13.
If you want documentation for GarageBand on a Mac, version 10.3.4 on macOS 10.15.3 Catalina, look at the user guide for the Mac version: https://help.apple.com/garageband/mac/10.3/
How to download additional loops is described here: https://help.apple.com/garageband/mac/10.3/#/gbnd9ed77587