I'll try and put it in terms most people will understand.
You draw a picture using only one color, and a V.I.P will grade it based on the quality of your drawing. You will gain points, which you can add to the RGB numbers.
For example, if I drew a drawing with 0 0 255 (RGB Blue) and it was good, I might get 25 points. I can add these points to the two color numbers that aren't 255. Let's say I added these 25 points to Red. I would have 25 0 255.
You can also subtract these points from a color number. For example, if I used my 25 points on Blue, I could remove 25 points from Blue, giving me 0 0 230.
Lastly, you can move points from one color to another. I could move 25 points from Blue to Red, giving me 25 0 230.