I'm in the same position. Downloading a trial of Management Server gives you access to the software for both that and Desktop Encryption, plus all the install guides and documentation for both, but we have only been sent a license for the desktop encryption.
The Symantec_Encryption_File_Share_Eval_Guide.pdf states to install the management server first before installing and licensing Desktop Encryption. I'm not 100% sure I need the Management Server to test our requirements, but I'm currently struggling to share keys with other users from Desktop Encryption so I presume I might.