Press the corresponding keys on the piano to play the note. Click the resistance pedal next to the piano to emphasize notes. Press A to start the stopwatch, and press S to stop. Note, it doesn't always work the first time, so try spamming S. Press D to set the stopwatch back to 0.
Took me a long while to finish it, I just never thought about it. At least it's done now. Please like and fave. :) Happy Birthday: QQWQTR-QQWQYT-QQTREWQ-YYTRTT