There are two possible configurations for using a Fathom multi-user license: Install on each machine (the type of license you bought tells you how many computers you have permission to install Fathom on); Install on a network server (the type of license you bought tells you how many computers you have permission to run Fathom on). Installing only on a server, and running Fathom from it, is less work to install and upgrade, though it will slow performance (by how much will vary depending on the speed of your computers).
Method 1: Use the CD with each computer.
Method 2: Mount the CD on your network server and share it so that it can be seen from each computer.
Install Fathom on the server using the CD. Make sure the application file is locked.
Make sure the Fathom folder is shared to each computer for which you are licensed, by whatever method you usually use to share networked software.
You may want to put shortcuts to Fathom on each networked computer.
Note: All installed sample documents are locked so that students cannot easily save over them. When students try to save, they will be prompted with a Save As... dialog. They must rename or move the file in order to complete the save.