As with many things in life, using PlayIt Live isn't simple at first, particularly if you are not familiar with the ideas behind media scheduling software.
Jason has made some super videos on PlayIt LIve and you can find them on YouTube.
Start with https://www.youtube.com/watch?v=GrOiuRugbko
and watch others from Jason's PlayIt Software channel.
Once you have watched the first video try adding some media to PlayIt LIve (music typically but could be any audio files) and experiment with getting the software to run through your selections.