Hi Colin,
You install BESR on one server known as the console server. This box will be used to control the jobs you run but you can save the images anywhere on your network. The only real requirement is that you have .NET Framework Version 2.0 on this server.
From this console server you push the BESR agent out to other machines (From console - Computers>Add>Deploy Agent).
Once the agent has been deployed you connect to each machine through the console you set up and run your image creation jobs.
Good Luck,
Gilly