Installing a clean Windows Server 2003 on a headless (no video out) system is not a simple task. I would not recommend attempting this without having either a lot of experience with OS deployment or a lot of patience and desire to learn.
There are generally two ways to do this on the EX47x series: one is to hook into the network boot loader used for recovery mode and push down an image, and the other is to use a pre-configured hard drive. With either method you must have an installation of the OS pre-configured. The most straight forward method is to take a hard drive to another system and install Windows Server 2003, then use Sysprep to prepare for an unattended installation.
I attempted to write a guide here; just remember this is not for the faint of heart.
NOTE: All credit goes to MediaSmartGuy whom I copied and modified these instructions from (and which are tested and known to work flawlessly — Thank you!)
If you just want the driver pack I’ve put together get it here.