there's actually no instruction on the tracks- although i have used those types of audio as well with good results. the holosync cd's contain specially designed sound waves (not exactly sure of how the science of that works) that are embedded in soothing music tracks. in conjunction with some concentrated thought, they really do inspire a more regulated sleep cycle that can lead to vivid and lucid dreams. (and although i dont want to advocate downloading music, you can search the terms "holosync" and "delta" or "theta" on something like limewire and hit the jackpot)