You’ll have to ask your hosting provider about that.
As James said, you’ll have to contact your provider.
For instance:
If your domain name is hosted with “Go Daddy”, and your website is hosted by “Host Gator”. You’ll ahve to get the DNS Name Server from “Host Gator”, and then input those addresses into go Daddy’s admin panel.
So when you type the url of “yoursite.com”. The url actually will then point to your server. “n23.hostgator.com” lets say.
However most hosting places I usually deal with include the domain register with the hosting services.
So check with your hosting provider first. I only have one site with the first method.
Hope that clears the process up. ( I was thrown a website at me also, years ago though)