SIMPLE explanation for enabling custom content profile CCK fields

I consider myself a fairly adept developer, but the instructions on how to enable custom content profile CCK fields to display on the author panel are very, VERY unclear.

Is it at all possible for someone to write out what the preprocess function should look like exactly for this task, what files to split it across exactly, and a couple example fields so that I can see them working, and hack away at it from there?

This is such a common task that I am surprised at how unclear the documentation is. A solid example, and not just a generic "this is how a preprocess should be built" function would be appreciated.

Thanks in advance!