After I made The Riddle of the Temple last year some people mentioned that the behind-the-scenes area with Phinxel (a little sphinx character) was helpful for learning a couple of things about making projects in Decker.
I've learned a lot about the program since then and so Phinxel is back with enough Decker facts to fill up a medium sized notebook.
https://ahmwma.itch.io/phield-notes
The book is divided into sections that each have their own indexes and there's a search engine contraption in the appendix if you're trying to find something specific.
It's a little silly but I really hope it's helpful!