The General section contains configuration settings that are global to the program. Settings such as the port the server runs on, and userid should run as.
The Admin server section enables you to modify some of the configuration settings of the administration server itself. This allows you for example to set the port number that the administration server runs on, password protect access to the administration server, and define what sites it can be accessed from.
The Server section is the major part of the configuration. This last entry will be displayed as either Create Server, or Server Configuration depending on whether you are installing Zeus Server for the first time or not.
Zeus Server can handle multiple virtual servers all running on the same port. In order to enable this, you need to configure your machine to accept connections on multiple ip-addresses. By creating a virtual server for each ip-address, and defining each virtual server to have different document roots, then you can set up a single physical machine which handles requests for both say www.foo.com and www.bar.com, but to the client they appear as two seperate machines.