As you can see above, there are four main tabs on the main window: Parameters, Process, Binaural beats and Write to file. I'm just going to focus on the most useful and interesting settings from the first two tabs.

Under Parameters, you can find the most basic tools to stretch your sounds. The screenshot shows the default parameters when you open the software and import some audio. 8x is the default stretch value, that may explain why so many of those youtube videos where using a 800% stretch.

The stretch value lets you set how much you want to stretch your sound. You have three modes here. Stretch and Hyperstretch will make sounds longer. Be careful with Hyperstretch because you can create crazily long files with it. There is also a Shorten mode that does the opposite, makes sounds shorter. If you want to make a sound infinite, you can freeze the sound in place to create an infinite soundscape with the "freeze" button that is just to the right of the play button.

Below the stretch slider, you can see the window size in samples. This parameter can have quite a profound impact in the final result. Paulstretch breaks up the audio file in multiple slices and this parameter changes the size of those slices, affecting the character of the resulting sound as will hear below.

Let's explore how all these settings will affect different audio samples. First, here is a recording of my voice on the left and the stretched version with default values on the right hand side: