To create say a looping effect for the sprite sheet symbol , you need to bindTimelineAction to the sprite sheet Symbol.
Symbol.bindTimelineAction(compId, "bird", "Default Timeline", "complete", function(sym, e) {
sym.play(0);
});
//Here bird is the name of the sprite sheet symbol and the above code is added to the stage "compositionReady" event.
I am attaching a simple sample for reference.
Thanks and Regards,
Sudeshna Sarkar