1 - click on a item in the Playlist listbox; 2 - choose 'Open File', 'Open Recent' or 'Favorites' in the Menu (at the window top-left corner); 3 - press the button : 
MidiRunner works also as a MP3 and CD-audio player, maintaining midi keyboard functions enabled ...
to display the function menu, click on the top-left corner of the main window or press keys Alt+M ...
an external MIDI keyboard can be used connected to the sound-card input port ...
to play the virtual keyboard, you can use also the PC keyboard ...
you can load also the standard .M3U .PLS playlist files into the "Playlist" window ...
there are many useful shortcuts to the functions - press "Shortcuts" button to see the explanation ...
an useful help-on-line is available; press Alt+F1 to show it ...
to quickly open a file press keys Alt+Shift ...
to stop playing a file immediately press the ESCAPE key ...
to open a file you can also drag its icon into the Player main window ...
to add a file to Favourites List press keys Alt+S ...
to add a file to Playlist you can also drag its icon into the Playlist window ...
to add more files to Playlist drag the entire selection into the Playlist window ...
you can reduce the windows size to small toolbars by double-clicking on the windows top border ...
to quickly change the instrument of the virtual keyboard press Shift+Up/Down arrows ...
to reset MIDI file to original instruments, notes, volumes press the "R" button beneath the arrow buttons ...