you can choose whichever octave you wish to play in (higher or lower) on the keyboard, depending on whichever sound you think is nicest.
However, the beginners style (FastPlay) has chords in the left hand, which generally means both hands are played an octave higher than the advanced styles (SingPlay and ProPlay), which have the chords in the right hand and a bass part in the left hand.
regards
Declan