On your keyboard: The row beneath your number keys are natural notes, and two rows beneath that are more natural notes. The row with the numbers on it has sharps and flats, and so does two rows beneath that. Left and right arrow keys change the instrument you play.
Intro by @PullJosh. Version History: v.1.2a 4/19/16: - Reverted back to 1.2a v.1.3 alpha 3/11/16: - Added experimental drums. Warning: can be quite loud and unpredictable. Space key should stop it. If tapping space doesn't work, hold it down for a couple seconds. v.1.2a 3/10/16: -Added more to the note length change feature. Press G to switch to 1 beat per note. Press L to switch to 2 beats. v.1.2 3/10/16: -Added note length change. Press S to switch to 0.5 beats per note instead of 0.25 v.1.1 ?/?/??: -Added multiple instruments v.1.0 2/6/15: -Initial release -Press keys on keyboard to play notes.