The first edition is just waiting for imagery by @ctietze and the online course will be one of my focussed work for the next couple of weeks.
The next Zettelkasten-related topic will be mapping.
This article might be of interest to you:
This will be one of the corner stones to connect the overall architecture of the Zettelkasten Method and thinking tools. Perhaps, I might even say integrate the tools with the environment.
The infobox on the right with all the *maps might be also of interest to you.
Cognitive Mapping is the initial reason for the image capture function in The Archive. It integrates the environment of thinking "desk" with the environment of thinking on your computer:
I am a Zettler