so, i have 1 domain name, already registered.
probably to access the site, i'll be needing to configure my DA's NS with it.
however, how would i configure my site (i.e, client DA) to work with the same domain name?
Let's say that your domain is bulbulon.com. You'd create a hostname in your DirectAdmin panel like server.bulbulon.com, and nameservers such as ns1.bulbulon.com/ns2.bulbulon.com.
You'll need to go to your domain registrar's control panel and register those nameservers, which is a free service with most registrars.
Setup your domain bulbulon.com in DirectAdmin's User Level section, and once everything propagates, you're in business.