Everything I know about the project came from the various responses to Anxiety Wizard's original Tweet here:
https://twitter.com/anxietywizard/status/1278198995559436288
But from what I can glean, basically anything you do is okay.
At least one person asked if making accompanying images would be fine and was told: yes, making your own illustrations will be fine.
The material folks generate doesn't have to mesh with each other, but no other guidelines have been given.
I know for my part: I want to do a bunch of stuff on my own; there are a bunch of ideas I've been meaning to get out of my head into some form of typed record for awhile. But if I get it done in time and other folks want to incorporate my material into their work, that's fine with me.