Melodica presents you with a screen of small boxes which you touch to activate. These boxes essentially represent a four-count beat with 10 different tones to play.
Once you activate a box, it lights up and plays a note in the sequence. Touching other boxes builds up the notes in your tune until you have a full sound and a cool looking light show.
You've got three tempos to choose from in Melodica-slow, normal, and fast. If you want to start over, just shake the device to clear the board. Once you're finished, you can save your creation and listen to it later.