Website hosting help

[Wossi]

My friends fiance is wanting to start up her old website selling photographs she has taken and I have agreed to host it on my webspace seeing as I have enough room. Now I've already set the limits so each site has an equal amount of space and transfer allowance and I'll be actually adding her domain name tonight. But while going through the faq from my hosting I came across something that got me stumped

You may have purchased an additional domain with ourselves or another registrar. If the domain was bought through 3dpixelnet, nothing needs to be done with the nameservers. If the domain was purchased elsewhere the nameservers need to be changed to point to ours. These are:

ns1.3dpixelnet.com & ns2.3dpixelnet.com

Now does that mean just the name or the whole shebang?

I assumed I just added an extra domain (can have up to 5) on my control panel and adjusted the limits accordingly and that's that. Or have I got it wrong? First time I've really played around with this stuff as you can see