How do I make a color set?

[Sicarius]

I wanna make my own color set so I can add special colors for my medieval RP.
Ive never made a color set before so can someone make me a tutorial or link me to one or something.

[Ad Bot]

[Demian]

I've used this too many times.
http://forum.returntoblockland.com/viewtopic.php?f=3&t=29