I imported the PSD to Krita and made a few changes to make it work! Just uploaded it - Hope it helps! :)
Heya! Unfortunately I don't have the time to make an additional video right now, but you would want to select the Walls transparency mask and select the rectangle tool with foreground color set to white - the tool options should be "Fill: Foreground Color" and "Outline: No Outline". That would allow you to make walls, same as the video!
Also, for the Airbrush, make sure that you're not selecting full-black but some sort of grayish black. Krita seems to interpret full black with hard mix as just black, which doesn't work for the hatching purposes.
I hope that helps!