Exchange Installation

I’m attempting to install exchange in my office. We currently have one server setup for our “fileserver” and I’ve just purchased another server and install a fresh copy of Server 03 Enterprise. I have Exchange 03 as well. That’s about as far as i’ve gotten. I’m not sure if i need to set it up as a child domain, or what? I’ve setup exchange before on pure magic, however; it was on SBS 2003 so everything was there and it was on the same server as everything else. Any help would be greatly appreciated!!