Greensleeves introduces the key of G major which has one Sharp - F#. Normally the sharp symbol is not shown when F# is played (but turning on Courtesy Accidentals from the Piano Booster setup/preferences menu will show all accidentals in the key signature). The melody is in the right hand with a simple left hand part.
Tip: V nastavení Piano Boosteru můžete zapnout Pomáhající posuvky. Ovšem nezapomeňte je vypnout až je nebudete potřebovat.