So you can scrobble and it gets you new music? But so, how can you listen to that new music?

You scrobble to record your listens, and then based on your listening history, there are many ways (in scrobblers and services that integrate with them) to get recommendations. Example: https://resources.onestowatch.com/how-lastfm-recommends-new-...

Rocksky itself isn't a streaming service, it tracks what you listen to from other apps/services and builds discovery/social features arround that listening history.