If you registered with a different domain name, you have to send in a support ticket requesting your domain changed to the new one.
IE. you register with 1234.x10hosting.com
you buy 1234.com
You send a support ticket to x10 asking for your site to be 1234.com
You go to your Domain panel from your registrar (GoDaddy, LimeDomains, etc.) and set the Name Servers to ns1.x10hosting.com and ns2.x10hosting.com
Please remember, it MUST have both nameservers set, or it may not work correctly
