To play Dropping Music you first need to select a song from the list offered.
The notes will start to fall from the top of the screen and you need to "play" those notes at the right time.
When the music note falls down, press the appropriate button (Either D,R,M,F,S or L) when the note gets to the corrseponding letter. You can obtain a score of 2 (GOOD), 1 (FAIR) or 0 (MISS).
Dropping Music will definitely offer you quite a challenge and it takes some time getting the hang of it.