See if those two orange wires are connected together inside the unit. If so just use one and tape up the end of the other.
The bigger mystery is the single field coil wire. You may have to ground the other field coil wire or connect it to +12V. There should be some instructions i think!
Anyway you can test it with a tail light bulb. Connect all the wires except the green one. Connect the bulb between the green wire and ground, then between the green wire and +12V. Whichever way lights the bulb when you turn the key on is the proper connection, just wire in the field coil in place of the bulb.