Bernie.

Please proceed as follows:-
* Press STYLE - MODE
* Press LOWER (U5/10) to access the CHORD MODES for the LOWER section of the keyboard.
* Press MODE (F5) and change value to 2 or 4 "Bass on stop".

To have the bass note sustain/hold when you release, press BASS (U3/8) and change the SUSTAIN value (F6) as desired.

Thanks,