How can I download Apple Music playlists for offline listening on Garmin music?

I’m kind of dumb on how to get the most out of apple muze so please bear with me. I’ve been considering canceling my subscription because I rarely listen.

One thing that might help me hang around is being able to access my playlists offline.

Am I able to load my downloaded tunes into my garmin music and listen on bike rides, hikes etc.

How do downloads work as far as limitations go?

Why are some songs able to be downloaded and others aren’t?

If I can connect to my garmin music how do I specify which tunes, playlists, etc., to load?

I guess the best thing I could use is an instructional vid.

Thinking out loud here. I hope someone can give me some direction.

Thank You

[Re-Titled by Moderator]