Domain name servers store all DNS records for a domain name. Most Top-Level domains (TLDs) require 2-12 name servers. Multiple nameservers ensure that if there's a problem with one server, other servers make sure your website still function.
How a domain name works
When you enter your domain name in your web browser, it first sends a request to a global network of servers that form the Domain Name System (DNS). Then, these servers will query for the respective nameservers associated with the domain name and forward the request to the DNS server handling your domain DNS.
How to change your domain name servers
Changing the name servers may sound complicated, but its actually very simple. It may however look different depending on which domain registrar you are using, but at their core, all registrar are the same. They will give you an option to manage your domain name and there you can access the option to manage your domain nameservers and enter your own name servers.
Before you can start changing your own name servers, you need to know which nameservers you need to use. On our free hosting service, you can use
nameserver 1: ns1.fnhost.org nameserver 2: ns2.fnhost.org
What's next after changing your name servers?
Any kind of domain name changes will take time to take effect worldwide, this process is usually called DNS Propagation and it really depends on the domain provider and dns server of your domain how long it will take to propagate.
Unfortunately there is no way to speed this up so you can only wait for DNS to propagate. You can try to flush your DNS cache and see if this helps in speeding up. This will flush your computer DNS cache and, in some cases, can help speed up your DNS propagation.
However you don't need to worry too much, the DNS propagation is fully automatic and will completely in at most 24-48 hours.