Read the stickies, it pays to have an idea of what you are doing before hand. Then goto PPCKitchen.org to download
BuildOS. Install BuildOS and run the updater. Select the Apache packages. It may take a while for all the packages to download, so read up on some more stickies while it's doing that. Then run BuildOS, Select your bootloader version and your carrier. Select a few basic programs and run the build. Don't add a grip of apps yet, get the basic build on the phone first and make sure it is all working.