if you wan to play something you must to loaded first , there are several methos in Mediarenderer device type, you can use the metod playTrack and it loads the uri of your sound and play it.
You can use some smart app to catch the event you want and start your audio.
Remember you need to use a control point to play your music and after that ST save each audio you has played , then you can use that save reference to play a track or sound.
try the [Updated] Media Renderer Events, play messages, radio stations, tracks, sounds