When you say that you purchased Cpanel, what do you mean? The reason I ask is because Cpanel aren't a web hosting provider. It's just a piece of software that you install onto a server in order to easily manage a web server.
If you signed up for a hosting company that uses Cpanel on the other hand, then it should just be as simple as changing the NameServer details. To do this you will first need to get the NameServer addresses from your hosting provider and follow the below instructions to update them on Godaddy's side.