You need to install the game in DOSBox, either on the Pi or on your PC. I would recommend your PC as it takes some time to extract the game data. You can find details how to do this at the link below.
http://dosonthepi.blogspot.co.uk/2015/01/run-dos-games-in-retropie_15.html#add-dosgames
Run insthd.exe in DOSBox to install and synd.bat to play.
