How can I have my own dns server to switch server for websites ?

Hello,
I run two VPS servers from contabo, Recently I purchased third server and I installed DNS server manager on it after a clean install of CWP pro, although cwppro not required for it but I purchase license because of other reasons. Now I want this third cwp server where dns server and manager is installed to act as a ns1.domain.com and I want previous two servers to act as ns2.domain.com and ns3.domain.com
So far I have configured added dns server manager and on 1st and 2nd server i have configured slave dns-manager inside dns function. It can push domains to dns server manager on third server.

1. so far its working. but in dns server manager at dashboard when i start, restart, or stop, whatever button i click it does nothing. (Status for named. Inactive). How do start this.?

2. My second question is how do I configure namservers for all all servers. So that I can have ns1.domain.com and ns2.domain.com and ns3.domain.com namservers which I give to my clients when they purchase an account from me.

As of now I have setup and created two different ns1 and ns2 on both old servers. I want to use dns server manager so that I can switch my cliens account from one server easily without delay and without them knowing it.

presenlty I am using cloudflares dns manager to do so, when i transfer client acount from one account to another by cwp to cwp migration I change dns A record in cloudflare dns manager.

Can someone help me understand this. How can i do this,

In godaddy i see they always provide same nameservers to clients no matter which server you are using, I want to achieve this.

Waiting for help from community.

you need cloud concept and some logic
cmiiw... i was use this concept at 2000-2005 lol
no cloud system at that time and i use CPANEL (the only one panel / the best one 'at that time' ) + whmcs

at domain manager you just need setup child

ns1.domain.tld IN A 1.1.1.1 server A
ns2.domain.tld IN A 2.1.1.1 server B
ns3.domain.tld IN A 3.1.1.1 server C
ns4.domain.tld IN A 4.1.1.1 server D

domain.tld IN NS ns1.domain.tld
domain.tld IN NS ns2.domain.tld
domain.tld IN NS ns3.domain.tld
domain.tld IN NS ns4.domain.tld

at whmcs i set NS :
ns1.domain.tld
ns2.domain.tld
ns3.domain.tld
ns4.domain.tld

when my client register via vhmcs let say client-domain.tld
it will create to server A
and set ns to ns1 2 3 4
then sync (with my friends tools) make clone to B C D

of course it was not cloud but almost like cloud system...
visitor client-domain.tld will load from nearest server
and that only work 50%-70% ... sometimes it always push to A

We stop play hosting and never update until few month ago i try to make money from hosting ( oot: im shocked... not easiest like b4 to sell hosting)

yes its very complicated thing, Like if i clone websites to all three servers and its wordpress site, how do i achieve database synchronisation.

And I dont understand the whole point of dns server manager thing, what is its porpose and why use it.

I do face problems when I want to switch my clients account from one vps to second vps or third vps, every time I do that I need to change a records of my my clients dns to point the website to new address, and I use cloudflare account to do this.

Acctualy I reque a software or interface like cloudflare where I can change my clients dns without them knowing, I am a freelance and I sell server to my own clients only, not selling it as provider. and also provide technical support to them, for keeping thier site optimize, thats why i host thier site on my own vps purchased from contabo.

Is there any softer or dns manager like cloudflare upon which i can manage my clients dns records/zones ?

Just buy aws cloud or google cloud

well little oot..

And I dont understand the whole point of dns server manager thing, what is its porpose and why use it.
>> try new concept.. and today we found the cloud server lol

how do i achieve database synchronisation.
i was use remote database in one server actualy lol
and use some "like" proxy stuff