yes, you have to keep the DMS amp off of the main network using its own switch, or use the MFS8 switch to keep the DMS's high traffic off of the main network.

you also need to program the DMS in the Total Control software.   Add an MRX10 to the project to get started.  Then add the DMS amp(s).  Add devices to the project that will be the inputs for the amp.  Then perform the DMS setup step to assign these devices to the DMS's inputs.  Set the IP address for the DMS in the network setup section.  Then download the program to the DMS.  

You don't need an MRX10 to do this, you just need to add one to the project.  I could send you a file that I made to use 3 DMS100's on a recent project if you get stuck.