1) Login to WHM (web host manager)
2) Under DNS functions, click Add a DNS Zone.
3) Enter your IP address of the reseller name servers above on the server your account is located.
4) Next, Enter your first nameserver in ‘domain’ field:

ns1.yourdomain.com

5) Click Do it.
6) Repeat this process for your second name server

You now need to create / register the name servers at your domain registrar. Please contact them to assist you, as each registrar has a different process.