It's required that you have installed CentOS WebPanel and at least one public IP address.
** Please note that some domain providers will require that you have two different IP's.
CWP.admin - DNS Functions --> Edit NameServers IPs
Add here add your subdomains you want to use for the NameServers and one IP for each nameserver eg.
ns1.centos-webpanel.com --> 188.8.131.52
ns2.centos-webpanel.com --> 184.108.40.206
If you are using one IP then it should looks like:
ns1.demo.com --> 220.127.116.11
ns2.demo.com --> 18.104.22.168
Don't forget that this NameServer must be registered with your domain registrar or they will not work!!!
How to Register your Nameservers with Domain Registrars
Enom Instructions: http://www.enom.com/help/faq_dns.asp
Godaddy Instructions: https://uk.godaddy.com/help/add-my-own-host-names-as-nameservers-12320