How can I setup DNS for my server?

Basically, you have three options to do so.

1. Leave the hosting of DNS with your registrar and create A and MX records towards the IP address of your server. This is the fastest solution to setup
2. Setup 1 name server on your own server and make it a hidden master for the name servers of your registrars. This also works with control panels. The advantage is that you can control your DNS from your own server and you use the (hopefully redundant) DNS infrastructure of your registrar. Please ask your registrar on how to set this up.
3. Run 2 name servers directly on your server. You need 2 IP addresses. You can request an extra IP address from the Tilaa dashboard in the networking section. This has a significant disadvantage. If your server goes down, your DNS goes with it. If you want to set this up. Make sure DNS is running correctly on both local name servers and that they are reachable for the outside world. Then change the name servers with your registrar and point them to the Tilaa IP addresses.

Tilaa doesn't have the possibility to use the Tilaa name servers at the moment.

Please take a look at http://en.wikipedia.org/wiki/Domain_Name_System for some background about DNS.

For control panels (DirectAdmin and cPanel) you can use the following documentation:
cPanel: https://forums.cpanel.net/threads/tutorial-nameserver-configuration-on-cpanel-servers.404841/
DirectAdmin: http://help.directadmin.com/item.php?id=283