HID ballasts use high voltages. Several hundred volts to run the lamp and a 3-4 kV pulse to start the arc. If you miswire it there is the possibility of even higher voltages. This is not a situation where you guess.
Usually on these ballasts there is a white common lead on both sides of the transformer. Black is power to the lamp, typically through the capacitor. I cant see enough to be sure but it looks like you have a multitap transformer which means that on the input side there are connections for 120,240, 408 volts etc. On all the ballasts that I have wired up the 120v input has been orange with the voltage written on the wire in small letters. There should also be an X3 tap on the transformer for the ignitor.
The circuit also needs an ignitor and a cap. The 70W HPS ballast that I have has all these components on a small circuit board. If these are not present, then the ballast is worthless since it costs as almost much to buy these separately as does the complete kit and the cap has to be matched to the ballast.
Wiring up a ballast kit that came New In the Box is pretty straightforward if you can do basic household wiring and take the time to be careful. I would not mess around with something like this that has lethal high voltage unless I was familiar with the circuit and had some understanding of it.
then I had to figure out how to hang these giant things and get them both under a homemade reflector. They came from a Budweiser brewery parking lot 
