You can only use music (radio streams/tracks/albums) for your sequences that are stored in your Sonos Favorites (My Sonos) or in your TuneIn radio stations.
Using an optional in-app purchase, you can also start sequences at specific times or via external triggers like IFTTT.
Of course, this requires that the iOS device is on the same network as your Sonos devices at the time.
With SonoSequencr you can create individual sequences to perform recurring tasks with just one click.
If you have multiple Sonos devices and want to play a radio station on all of them, it takes some time to set this up.