You can find the pairs of your stepper windings by shorting the pairs of wires from the motor and turning the shaft. When you find a pair you will feel the resistance of the winding. It is quite pronounced. Using that method you can find both pairs of windings. Then you can randomly connect the four wires from the laser to the pairs. You will either get lucky or need to try again. Process of deduction should reveal what wires go to what pair. If you need the stepper to turn in the opposite direction simply reverse one pair.