Motors like that are designed to be run off a switching or chopper driver. They are not designed to be driven of a very low voltage. You can drive them at a current of up to 1.2A.
So you need a stepping motor driver. I am not going to sit through 25 mins of some one droning on an on to find what sort of driver that video shows. I tried scrolling through but failed to find any actual circuit diagram but I suspect it is not the right sort of driver.
Your best bet is to get a stepping motor driver, they are only a few dollers.