Basic idea is that code is being injected into a script/style tags and content tags at the same time. (Contents tags are div, p, pre, etc.)
Put your code inside the "code" variable. When switching from CSS to JS or vice versa use "`" so the program knows to where to put the code. It's starts with the "style" tag by default so "`" will switch it to the "script" tag
IF you value your sanity, i suggest using Coffee Script. It's supremely easy to use, and that's where all the comments are.
I didn't make the autotyper, Jake Albaugh did. Here's the original post: http://codepen.io/jakealbaugh/details/JoVrdw
PS. I hate markdown.