Adding a second domain to a web panel on Digital Ocean

Hi there all! Yesterday i setup a droplet and installed Sentora on there and all seems to be working fine now. However iv seen someone comment on here showing how to create “vanity” nameservers, to do this i created “A” Records linking to the three DigitalOcean namservers.

However i am in the process of adding a second domain to the panel, here is what i have done:

1. Changed the domain nameservers so that they are linking to digitalocean using those nameservers i created previously.
2. added the domain to Sentora.

Will me doing nameservers this will actually work? I updated it on my second domain a few hours ago and nothing seems to have changed with the site yet? also I am wondering, everytime i want to add a new domain will i need to add the domain to the DNS page that is build into DigitalOcean? and then customize the DNS through there?

thanks! alex