1. Press the [SPLIT] button (right hand side of the panel next to the voice buttons).
2. Press the [VOICE EDIT] button (to the left of the [SPLIT] button).
3. Press the [A +] button (To the left of the LCD screen) to change the option to Left.
4. Press the [C+] button to get to Pedal 1 (or 2, 3, 4 if the sustain pedal is plugged into one of those jacks).
5. Press the [D+] button to get to Sustain.
Do you need an additional help?