The concept is pretty simple. It's an app for listening to music. There is your personal library, recommendations, radio station etc.

I honestly don't know how the app could be made any simpler.

> I don't get what the underlying concept is

It's an app for listening to music. You get a search box and a list of music you've saved. What more concept is there to get?

Thank you! I agree completely. It's like there's some flow that it's optimized for, but I have no idea what that flow is. I want to find music, then play music. Half the time when I search, it doesn't find anything, even though I know it's there. The other half the time I search, it shows me an overwhelming number of possibilities, each slightly different, with no way to tell which was the one I intended. Then there's the "card" that pops up with what's playing, but which won't come up when I need it to, and always comes up when I'm trying to do something else. The buttons to do something with the music, like add it, remove it, etc. are never where I think they're going to be, so I end up playing point and click games like some bad adventure from the 90s. "Does this control do it? Nope. How 'bout this one? Nope. This one? That's it! I've unlocked a basic feature that should have been obvious!"

The only thing that I miss from the Apple ecosystem is Apple Music. I like to listen to music by albums, and Apple Music does that wonderfully. Spotify seems to be tailored to consume music on a track by track basis.