Use the single stepping buttons to move up and down through the midi messages.  With each step the active notes at that point of time are displayed along with the corresponding chord symbol, if any.

Single stepping is like playing the song in super slow motion.  Because you are stepping from an actual recorded performance, you can easily see the order in which the fingers touch the keyboard, and in the process which fingers you tend to favor when playing.  This allows dvanced pianists to analyse and correct their performance.  Beginning pianist should be happy just to hit the correct notes.