Click the green flag in the top-left corner or the center of the project screen, and use the keys on your keyboard to play the piano. If you want to play the sharp/flat keys, hold SPACE while using the keys. There is also a settings menu that shows when you click the gear icon in the top-left corner inside the project. The piano has three different display modes which are: Blank: The default. Doesn't show anything on the keys. Notes: Displays the standard A-G piano notes on the keys. Keyboard: Displays the computer keyboard keys on the assigned piano keys. You can change this with the Keyboard Key Offset slider. If you don't know which keys play which note, I recommend setting the piano to this mode. There are also other settings such as: Piano Height: Determines the height the piano is from the lowest y position. Note Length (in Beats): Determines how long a note will play for. This also depends on the tempo. You cannot play the same note twice while the note is still playing. It's kinda weird I made it this way, but oh well. Tempo: Determines the BPM for the notes. Show Grid: This changes the background to a grid that seperates the piano into A-G sections. This can be toggled on or off. Once you're done playing with the settings, click the X in the top-left corner inside the project.