Click the "raw" button at the top-right of this box to see the unrendered (aka "raw") version of this guide. Some of this guide will only make sense if you also see the "raw" view, so try and view these side by side.
You may also find it helpful to look at the Example Project.
For the most part, you'll be using Markdown. It provides a nice syntax for things like headers, bulleted lists, and links.
Markdown is not a "What You See Is What You Get" format. Because of this, I recommend that you write your post in a markdown editor, then paste it into the body field of the Project or Article. It will make your life easier.