[Plugin: Portfolio Slideshow Pro] Synchronize audios with individual slides?

I’m making a meditation slideshow with images to meditate on, accompanied by both background music for the entire slideshow, as well as audio narration for each individual slide. The narration will relate to what is specifically on that slide, e.g., “as you look at this dandelion notice the spore floating in the wind.”

How do I set an individual audio recording for each slide?