Mac OS X Server can be configured to provide a wide range of services, to suit the needs of a variety of network environments. (See the official Apple documentation above).
The documents below provide a (non-official) step-by-step guide to setting up an OS X 10.7 Server to provide basic network and collaboration services that meet the needs of a typical school environment. The documents are listed in the order of the installation and setup process.
The model described in these documents is by no means comprehensive, nor prescriptive, and may not necessarily be suitable for use in your particular environment. However, the notes below describe the configuration of a model that will support school learning environments, while being technically 'supportable' by teaching staff or others who do not have extensive knowledge of server technologies.
As always, some testing and experimenting on non-production equipment is advisable. (Lion Server cannot be installed on pre-Core 2 Duo computers.)