To configure your own name servers in cPanel/WHM please follow the steps below:
1. Make sure your VPS has a proper hostname (like "server.mydomain.com", where mydomain.com is a domain you own and added in cPanel/WHM). You can change your hostname from Hypanel -> Machine Settings -> Set machine hostname
2. Login to cPanel/WHM.
3. Search for Edit DNS Zone and click on it.
4. Click on the domain you want to use for nameservers to select it, and then click on the Edit button.
5. Add ns1 and ns2 records as shown in the image below according to your VPS IP (you can see your VPS IP(s) in Hypanel). You can use 1 IP for both records if you only have one IP.
6. Save the DNS zone.
7. You also need to add the nameservers ns1.mydomain.com and ns2.mydomain.com to your domain register. Go to the company you bought the domain from and setup ns1.mydomain.com and ns2.mydomain.com with the IP(s) you set at step 5.
8. Check to see if your domain has the proper nameservers at www.intodns.com/mydomain.com (where mydomain.com is the name of your domain).