UBB.threads PHP Forum Software Community Forums UBB.threads Version 7/8 Support Forum Settings vs Category Settings

Hi experts:

I am the admin for a board and a bad one at that -- but I try. I am confused, because I add forums under forum settings, let's say they are called:

Red
Blue
Yellow
Green
Orange

But, then the very next setting is called Category Settings, which I never touch. It has something like Yellow and Green.

I do not understand what Category Settings are for.