To attach a sound to a timeline:
Select File > Import to import a sound.
Select the sound in the library, right-click (Windows) or Control-click (Macintosh), and select Linkage.
Select Export for ActionScript and Export in First Frame; then give the sound the identifier a_thousand_ways.
Add a button to the Stage and name it play_btn.
Add a button to the Stage and name it stop_btn.
Select Frame 1 in the main Timeline, and select Window > Actions.
Add the following code to the Actions panel:

var song_sound:Sound = new Sound();
song_sound.attachSound("a_thousand_ways");
play_btn.onRelease = function() {
    song_sound.start();
};
stop_btn.onRelease = function() {
    song_sound.stop();
};


This code first stops the speaker movie clip. It then creates a new Sound object (song_sound) and attaches the sound whose linkage identifier is a_thousand_ways. The onRelease event handlers associated with the playButton and stopButton objects start and stop the sound by using the Sound.start() and Sound.stop() methods, and also play and stop the attached sound.