The best way of learning how to put together a custom Android build is to start by studying the way that the .tar files are structured, I started by using 7-zip to study and change some of the files, ( you can really mess up your android doing this
However you will need to have access to a PC running Linux for some of the more advanced tasks. There are ways of running Linux without disturbing your PC's partitioning, but honestly, a dual-boot is the best way to go, you only need about 10-50GB of hard disc space for a decently set up Linux install, (10GB is enough for a well set up slackware based install like zenwalk).
Good luck on your journey into Android
XDA IIi ROM: 1.11.00 WWE Radio: 1.04.0 ExtROM 1.11.171 WWE
HTC Kaiser 1: ROM: Polymod 2.1D Final-Dark : Radio: 126.96.36.199
HTC G1 Dream: GammaFly V1.3 RC2, AmonRa, DangerSPL, Radio 2.22.27.08
Polymod 2.1D Final Version: It's Alive!
Android boot splashes and boot animations
(for Kaiser )