This episode is special, as it is not about programming concepts in general, but about how to add sound to a processing.js program. You won't miss any important programming concepts if you skip it.
Currently in my Chromium browser in Ubuntu, the sounds play only once. I noticed I could fix this by calling .load() on the sounds before playing them. I hope this is solved in the future, as calling .load() sounds not very efficient. You can try what happens if you remove the .load() lines.
The files from this episode can be found at: https://github.com/hamoid/Fun-Programming/tree/master/processing/06/e141_pjs_audio
Challenge: make changes to the program so instead of two functions to play two sounds, you use just one function, and send the sound ID as an argument. Instead of playSound0() and playSound1(), use playSound(0) and playSound(1).