SUSTAIN PEDAL
The sustain pedal (rightmost pedal) functions in the same way as the damper
pedal  of  an  acoustic  piano.  When  the  sustain  pedal  is  pressed, notes
continue to play after their keys have been released. Releasing the pedal will
silence the sustained notes.
SOSTENUTO PEDAL
If you play a note on the keyboard and press the sostenuto pedal while the
notes are held, those  notes  will  still  sustain  as  long as you hold the pedal.
But all subsequently played notes will not be sustained.
SOFT PEDAL
The soft pedal reduces the volume while the pedal is pressed. The soft pedal
will not affect notes that are already playing when it pressed.
Soft Sostenuto Sustain
Pedals