Note: If there are additional animations on the slide, be wary about the order of the sounds on the animation pane and selecting Start With Previous. One might think that was all it took, but your work is not done.
What if you want to play two audio files automatically at the same time (say, for example, you want a song to play but you also want a recorded narration to play simultaneously)?
A couple of weeks ago I discussed some points for working with Audio in PowerPoint today, a bit of elaboration.