OFB-9

Is this understandable? Or should it just be memorized? If it can be understood, could you provide an approximate sequence of reasoning?
Thank you very much!

I based my reasoning on the logic that a Swiss system is usually used in chess and checkers competitions; after the draw, the player listed first plays with the white pieces; in our case, this would be red. That's how it works.
P.S. - No need to thank me.