Commands on GoPiGo does not work


I assembled GoPiGo with Raspberry Pi and image downloaded from dexter industries. I updated everything and installed according to the instructions.
My Raspberry Pi boots up and i can do vnc into it. and then execute the basic python script which gives me options to issue commands to move GoPiGo. When i issue commands nothing happens, no error messgae nor any movement of wheels.

How do i debug what the issue is? How do i know my GoPiGo circuit is fine or my motors are fine?