NameServers: NameServers hold information for a website domain relating to the IP address for that web site called an "A Record", they also hold an "MX Record" which is used to identify the mail server.
Think of these records as a version of the telephone book for the internet. When you look up a domain name they will return the physical address (IP address) on the internet of exactly where your internet browser can find that domain.
For any domains that you have hosted with Pay Monthly Hosting your NameServers will be as detailed in your New Account Information email.
If you have your domains registered elsewhere but have your hosting with us, you will have to physically change the details of the NameServers with your Registrar to be as shown above. Any domains registered with us will have their NameServers set automatically.
Domain Name Servers: Domain Name Servers are a special network of servers on the internet that store domain names and their associated IP addresses for a limited period of time in a temporary store or cache. If a request for a domain is made, and the DNS server does not have that address in its cache, the DNS Server will make a request to another set of servers that hold the addresses for all the NameServers and return the IP address of the domain.
When you change any of the address details for your domain it will take a certain amount of time for this information to be updated across this network of Domain Name Servers. This delay is called "Propagation" and can sometimes take up to 72 hours to finally complete.