So... I think you turn the screw all the way counter clockwise. Then put the key in the ignition and turn it to on. Then turn the screw all the way clockwise and it should start flashing like 1, then 2, then 3, then 4. Those are the different 'modes'. When it only flashes once, that's mode 1, so turn the screw all the way back counter clockwise and turn the key to off.
Please reply if that's not working for you.