Essentially, you login to the site where you purchased the domain, and replace the default nameservers with the ones supplied by GlowHost.
If you are unsure how to change your DNS at your registrar, check with your registrar's documentation for how to update your DNS. The exact steps can vary between different registrars, but the idea is still the same no matter who your registrar provider is.
If you have registered a free domain name through GlowHost.com, and require a DNS modification, please see below.
DNS Modification for Free Domains acquired at GlowHost.com
If your domain name was registered free at OnlineNic on behalf of GlowHost.com, GlowHost now offers facilities for you to directly edit your DNS for the domain.
In order to change your nameservers, you will need to login to your GlowHost account manager located at http://glowhost.com/login/client.php
Once logged in, click "Manage My Domains" and you will see an option to edit your nameserver information.
The other option is to transfer the domain to InstaPro.net where you can get a one year domain name registration extension, the transfer, and a web based control panel that supports unlimited nameserver changes. The fee for the transfer is $14.95 USD and includes everything you need to change your DNS (nameserver information) and again includes a complimentary one year domain name renewal and extension of any time remaining on the current registration.
If you plan on pointing your nameservers to another host, GlowHost strongly recommends to transfer your domain registration to InstaPro.net.
To learn more, go to InstaPro.net and click on the domain transfers link right below the domain name search box on the top, middle of their homepage.