Rktcr 3.1's level editing support allows anyone to make and share challenge levels. However, the editor is a morass of undocumented keys and hidden UI. Or perhaps it's better to say it is streamlined and designed for rapid use by skilled practitioners.
Regardless, it seemed like a good idea to produce a series of tutorials to explain its use. In the first of these, I explain how to start Rktcr in editing mode and how to create a portal, gem, and platform.