Need to help to customize UCLinux for a variety of circuit boards with embedded MicroBlaze processor(s)

I'm a H/W engineer who is new to this and needs a breakdown of what needs to be done and why.

Complex howto not needed here (but would be appreciated for a Spartan-3E Starter board ) I have successfully gloaded Lynux to this board, but what if I am designing my own and need to customize uCLinux?

What I really need is a breakdown and overview of what I need to know. I cann then try some things and ask some more meaningful questions.

I know some great trickery with VHDL and might be able to return the favor.VHDL