4 step to how to add an audio from file in your powerpoint presentation.
___1.click the audio button.click the downward arrow below the AUDIO BUTTON and select audio on my pc.then click OK.
___2.choose the slide where you want the audio to appear.from the menu,click the INSERT tab.then go to MEDIA CLIPS.
___3.reposition the sound icon that will appear on your slide.
___4.find the audio that you want to insert.click on the audio once to select it and click insert button.
Explanation:
i hope this will help you