Navigate back to your channel again. You will now see your channel playlist alternates between the Skateboarding and Stags programs. You can now start your channel via the button on the top right of the Channel console.
Once it is running, select the Outputs tab and copy your unique playback URL.
Open up the player supplied here, paste in the playback URL and click Load Stream
Playback should begin and you should see your programs looping interspersed with 15 second ads.