DNS and other newb questions


I just got a VPS account and have a couple of questions about DNS. I'm pretty sure I understand how the DNS system works overall, but I'm unclear of some of the configuration aspects. Its my first VPS.

My domain is registered at enom. I have registered ns1 and ns2 as name servers at enom pointing to my two VPS ips.

My vps is host1 .mydomain. com.
If I point my browser there, I get a default apache page.

In WHM, if I click "Add an A Entry for your Hostname", it shows it set to the first VPS IP address.

I copied over a couple hosting accounts as a test. There is a DNS record in WHM for booth domains.

Now, if I go to w w w. mydomain. com, one of these other accounts show up.

I do have a DNS record for mydomain.com but no account. I'm afraid to delete it because I don't understand its relation to host1 .mydomain. com. There is an A record in the zone entry for "host1" (as well as ns1 and ns2). Should I just delete it and then have it created again by creating an account with that domain, then manually add back in host1, ns1, and ns2? it wont let me create an account for a domain that already has a dns entry..and I'm not sure how that effects the rest of the server (having an account with the same domain as the server)

My intent is to have my hosting site at w w w .mydomain. com

I guess I just don't understand what maps a particular domain to a particular account on the server. I thought apache just looks at the the http request headers to match the domain with an account so I'm puzzled as to why one of the other accounts would appear when going to mydomain.com

Also, can someone give a practical example as to how I should utilize my two IPs? Is it bad to have all accounts on one IP?

Thanks for the help,
Regarding " Is it bad to have all accounts on one IP?" the answer depends. A dedicated IP is generally only needed for an account if you need to install an SSL certificate for an account or you want to use anonymous FTP.