I decided I just might to jump into this, so me and my oldest son went down into the basement tonight and got busy. He was in charge of the hairdryer, and I held the airbrush
First a shot of our paint-booth:

I have an old kitchen in the basement, so I simply use the ventilator from where the oven used to be. I will transform more or less the entire basement to a hobby room later, but this will do for now....
I started out by removing all the masking where the black was supposed to go:
Then i laid down 3-4 coats with the black; which turned out somewhat more charcoal in my mind; it was a black pearl, rather than the flat black I though I bought...
Never mind, I then started by removing the first area that was to have some color,
...and laid a thin layer of orange in the front, and yellow over the rest:

This was before I backed with the pearl white, so the colors were not that vibrant...
I continued to build the colors in the various fields, using only orange, yellow and the white, and after an hour or so, it came out like this:
I am quite pleased for being the first time, and once the daylight is back, I will bring out my proper camera and take a few more pictures of some details, especially of the areas where I have some questions.
The liquid mask was a pleasure to work with, but I see I need more practice with the scalpel...