This plugin uses the Retroshare Turtle service. To compile it copy it alongside the other RS plugins in the source. Build RetroShare and then simly type $ qmake && make
Then copy the resulting lib into %APPDATA%\Retroshare\extensions on Windows ~/.retroshare/extensions on Unix / Mac
on *nix like OSes you need to rename it from libTortoise.so.1.0.0 to something like Tortoise.so.
Then start Retroshare with at least 3 instances where the friendship graph is like this: A<->B<->C.
Wait until everyone is connected. Then: Enter any string in the field "Server Hash" and click "Listen to this". Then enter the SAME string in the field "Cliend Hash" and click "Monitor this". Then send Messages back and forth.