Setting standalone nameserver

Dear Sir/Madam, I am new to cPanel/WHM, I have similar case as the thread addon domains error message: "the domain is already pointed to an IP address that does not" but I have no idea where I should add the nameserver setting, from cPanel or WHM? I have a new domain say newdomain.com and new VM with hostname say newVM. I have an existing nameserver say ns1.existns.net, ns2.exisnst.net I register the newdomain.com from the registrar and point the nameserver of this domain to ns1.existns.net and ns2.existns.net, ip of newdomain.com is pointed to the ip of newVM. On newVM, I create a new cPanel with primary domain as newdomain.com, I setup the Basic cPanel & WHM Setup -> Nameservers with ns3.exsitns.net and ns4.exsitns.net which both ip are pointed back to its newVM ip, of course I do add the A record for ns3 and ns4 on exsitns.net I click into the Advanced Zone Editor, I found the A record of newdomain.com is pointed newVM ip address and CNAME record of ftp.newdomain.com is pointed to newdomain.com Now when I nslookup the ip of ftp.newdomain.com from outsider, it is pointed to ip of ns1.existns.net and I cannot able to resolve the ip of ftp to newdomain.com ip What's wrong I did on the setting? If I want to have the newdomain.com to be a standalone nameserver and all new coming addon domain created on this cPanel can be propagated, I don't want to update the coming addon domain on existns.net. Here is the summary of the setting. existns.net > nameserver ns1.existns.net, ns2.existns.net > DNS setting ns3.existns.net, ns4.existns.net, newdomain.com (point to newdomain.com ip) newdomain.com (primary domain on newVM) > nameserver ns3.existns.net, ns4.existns.net I would appreciated if anyone can help the newbie like me. Best regards, Kelvin.