Once you've chosen a level to play in the main menu, playing the music minigame is as simple as tilting the device left and right to move your character, and tapping to jump. 

Collect three pairs of wings to transform your Winx. Once transformed, holding your finger down will make your character fly. 

Different notes are worth different amounts - collect as many as you can to unlock a cool new reward to use in the Poster Maker!