Setting up a server from scratch

[UCSC Student]

I haven't done any web-server or DNS work before and would appreciate it
if someone could tell me how to go about setting up a site.

When I register for a domain at Network Solutions, lets say "abcd.com",
what do I put in for the various addresses (administration, technical,
billing)?  I plan to host the site on my computer in my college dorm
room.  How do I make sure that the database has my IP address associated
with abcd.com?  Can I change this later?  I read about people setting up
primary and secondary DNS servers.  Do I need to do this?

A question about subdomains.  How do I set up a subdomain
(food.abcd.com)?  Do all domain names ending with "abcd.com"
automatically reach my webserver?  I am worried about this because when
I tried going to asdflkj.yahoo.com, I didn't get an error from Yahoo's
web server but instead I got a host not found error.

Thanks.