I got my welcome email, and it lists something called "Nameservers". What are these?
Believe it or not, computers don't have names, they have numbers (IP addresses). Think of it like a telephone book...the telephone doesn't know people's names, it just understands the numbers. You need a telephone book to be able to match the numbers up to the names.
Computers are the same way. A 'Nameserver' is simply a telephone book that links up your website's domain name (ie www.yoursite.com) to it's number (ie 234.123.345.6).
Your welcome email will contain 2 Nameservers, something like ns1.bluelantern.net and ns2.bluelantern.net.
OK great, but what do I do with them?
There's one more missing piece to the puzzle. Your domain name is 'registered' by a registrar - if you bought your domain name at BlueLantern, then we are your registrar. But perhaps you bought it somewhere else, like at Network Solutions, or Go Daddy, or Enom, or any of the other myriad of registrars out there.
What needs to happen is for you to tell your registrar where to find the telephone book for your domain. If you bought your domain from BlueLantern this is already done for you and you don't need to worry about it. If you bought your domain name elsewhere, you need to log in to your account and put in the nameservers (ns1.bluelantern.net, ns2.bluelantern.net, or whatever was specified in your welcome email).
Usually, the nameservers are under Domain Management or another similar heading. You'll find a spot where you can enter the nameservers (usually there are places for four or more, but you only need two).
The end result is that when people type your domain name into their web browser, they are taken to your hosting account and can see your pages.