Setting Up New cPanel Server Question About DNS

Hello my friends, In new on cpannel and i need your help if any one can. The situation is like this, we have a cpanel server on my company with 2 dedicate name servers, and we have 15 clients that have hosting and mail there. My boss what me to create a new cpannel server for a new customer (an important one). now i know how to install the server, but i dont know should i create another dns server or i can use the one that i have for the other cpannel? The client is going to host there 3 domains and for each domain is going to have a mail mail hosting and web hosting. can some one help me with the right way to start the instalation and configuration. Thank you in advance