Another note to add. The sound I want to play is supposed to play at the same time as animation that plays in a movie click when a button is clicked. So another way to approach this would be to have the sound on the timeline within that movie clip so that it doesn't play until the animation is told to play by clicking that button. This would mean adding some sort of code to the root timeline though that tells that sound to not play because it is right now, even with the movieclip stopped the sound still wants to play.
In any case, if you want to play a sound that is imported when a button symbol is used, then you can simply add the sound to the button's timeline at the Down frame. Since you're playing the sound from the timeline, you'll have no real control over the volume or stopping the sound.
If you want to control the sound using Actionscript, then here's a tutorial that may help to explain the process: AS3: Sounds