Audio Video Snyc Question

I’m making a video that is sopposed to play certain animation clips in other layers of the timeline at certain points. I know I need a “stop();” in on of the layers somewhere but am not sure. More importantly I can’t figure out how to get the clip to play during the mp3 file, it (currently) doesn’t play until I hit the stop button. Heres what I’ve got so far. The whole movie needs to start from one ‘play’ button. Any help is great help. I’ve been on a crash course to learn AS, and I’m getting the basics down thanks to the help I’ve gotten on here. I’ve been using a tutorial on that has helped 100%, but isn’t quite getting what I need…

firstSound=new Sound();
if (playing!=true) {

//this is the animation clip that I need to play at 10 seconds into the mp3

this.onEnterFrame = function(){
if (firstSound.position >=10){

Thanks if you can help me out!