I'll assume you're going to use a commercial hosting service for your site. Once you've registered, i.e. bought, your domain name on GoDaddy.com - which I recommend - and you've created an account with a hosting service, the hosting service will send you a code, called the DNS pointer or something like that, that you need to associate with your domain name by logging onto GoDaddy. If you later change to a different hosting service, that new hosting service will send you a different DNS pointer code and you'll have to logon to your GoDaddy account and change it.
