The Wiki tutorial is the place to learn how to use the formatting tags we use in the wiki and in the device's description section. A great way of learning is by writing wiki entries and improving documentation.
On Discover your hardware page, you'll learn how to obtain detailed information from your hardware, so you can insert it to the database. You'll learn, for example, how to find VendorID:ProductID codes of your hardware.
The compatibility classes are the way we rate hardware performance in general. With these classes, it is easier for you to know how to rate a particular device.
On Fully free GNU/Linux Distributions page, we keep a list of distros of which you can use to test your hardware for the h-node project. As you'll see, these distros commit only to use and recommend free software. All these distros are approved by the Free Software Foundation.