How do I listen To apple classical on a plan (offline)

From my experience, if you use the search (magnifying glass on the bottom right) within the app, you can search for classical and choose from an assortment of filters. Make sure to select Apple library and not “my library” so you find things you can add TO yours, and then when you’re ready to add something to your collection, you want to hit the + and then do it AGAIN and select download so that it’s available offline once it finishes.

Download it in the Apple Music app.