HELP!!!!!!!!! 2003 AD/DNS with dyndns

Hello please help,

I have created a dyndns account; I have 2003 server with currently 2PCs and a laptop with my home network. I would like to have AD setup on my server to authenticate users when they log on. I have a Linksys router that support dyndns. I have it set up and working, I have remote desktop just fine, however I?m lost with what to config in order to use the 2003 for an AD/DNS and file server. Please let me know what additional info you need from me in order to help me better understand how to set this up.
Thanks in advanced.