If instalation process was succesfull, it should be possible to run program simply by typing "mmapper" in command prompt. If you are running programm for the first time, it will load default settings and no map data will be loaded in memory. All default settings can be changed in Preferrences dialog (Settings/Configure MMapper). You should open existing or create new map datafile. There is also option in Preferences dialog, that allows autoloading data file when application starts.