the G3 have multy speed option .

mode a :  max speed 6 km/h   start by push

mode b max speed 12 km/h start by push

mode c  use 3 speed (low acceleration)  the speed are  12 km/h  , 20km/h  and 28km/h

to set the speed move the mode to c .

now , prees and hold the left brake +  throttel push  for 5 sec.  release the throttel and release the brake .  now the speed will change

mode d  , change the speed same like change for mude c
mue d is high acceleration.