Please, take your time and read tutorials for cex2dex conversion and purposes of it. It's really nothing personal, but repeating the same a thousand times just seems to be improper for me, and other folks could use the excercise. So please, don't be mad and read it all by yourself - it's wide open anyway. Starting from here - www.ps3devwiki.com/cex2dex and so on.
DEX is the firmware used by devs. That's the basics. Is there anything specific you aren't clear about?
nah leave it ... i know its not for noobs