You can add a sound to any page or object on a page in your publication. A sound can be as simple as a sound effect when you click on an object or it can be background music or voice over for a rolling demonstration.
There are two ways in which you can add a sound to a page:
Sound Tool – The Sound tool 
on the Tools toolbar allows you to quickly add a sound to any object on a page. The Sound tool automatically sets up a Left Mouse Click trigger and Play Sound action for you on the object’s Actions dialog.
Play Sound Action – The Play Sound action in the Audio/Video tab can be added to any trigger in a page or object’s Actions dialog.
When you want to quickly add a Play Sound action to an object that is activated by a Left Mouse Click trigger, use the Sound tool on the Tools toolbar.
When you want to add a sound to a page or, if you want to add a sound to an object but not to its Left Mouse Click trigger, set up your own trigger and Play Sound action on your page or object’s Actions dialog.