I don't have this computer but from what I read on this page, the Phase 1 section has a package of files. In that package of files is a script that will set some parameters for you. In Phase 3, they tell you how to run that script and that will set the parameters for various things including networking.
From doing the steps, Phase 1 gets the install drive ready. Wont run once I am booted to MOS. I have upgraded to 10.6.2 but can not go past that and I have no network or bluetooth and I can not find kext files for dell hardware