I found a radio station in Google Music that I liked. How do I add it to my favourites so that I can listen to it again?
There doesn't appear to be an option to save a station from the view of the playing song or the view of the playing queue. However, if you go to My Library, and then slide over to the Stations tab, you will find a list of Recent stations. If you select Add to My Library from the ... menu of the station, it will appear in a separate group below Recent stations called My Stations.
Pull up the station's "homepage" (where it has the station's description and lists artists on the station) and there should be "Add to library" next to "Share". Click on that. Now, it will show up in your "Music Library" under My Stations. This is different from "Saving" the station where it creates a playlist for the station - this is, in effect, bookmarking the station.