We've got buttons, now for some sound with those buttons!

Step 1 - Make sure that you've turned off
'Enable Simple Buttons' and pick one of your buttons.

Step 2 - With the Arrow tool, double click on one of your buttons.

Now add a new layer and name it Button 1 - Sound. Insert a Key Frame on the Over State.

Step 3 - Open your Common Library of Sounds and pick a sound that you like (do NOT obsess over this)

Step 4 - With the Over State selected drag your sound onto the Stage

Notice it will now appear as a sound wave on your Timeline.

Step 5 - Click back on Scene 1 and
Enable Simple Buttons and check out your button with sound.

Continue to experiment with this by adding a sound to your Common Library Button.

You can also experiment with which state you add your sound.