Hyundai NEXO 2019 Owner's Manual page 274

Driving your vehicle
Button Position
Press the POWER button while it is in the
ACC position without depressing the brake
pedal.
ON
To start the vehicle, depress the brake pedal
and press the POWER button with the gear
in the P (Park) position.
START
5-8
Action Notice
Do not leave the POWER button in the ON
position when the vehicle is not in the ready
( ) mode to prevent the battery from dis-
charging.
If you press the POWER button without
depressing the brake pedal, the vehicle does
not start and the POWER button changes as
follows:
OFF → → ACC → → ON → → OFF or ACC