The stepper wiring ports on the A4988 are identified as 1A, 1B and 2A, 2B. I am assuming that 1 and 2 refer to coils 1 and 2. And I do have the data sheet on my stepper that shows the coils by color (BLK/GRN & RED/BLU).
How do I translate the colors into the Pololu’s designations? How do I connect the stepper to the driver, in other words?
If there are only two coils and four wires, the only problem is to identify which two wires belong to each coil. You can do that with a multimeter on the Ohms or continuity setting. After you have made the connections, if the motor is rotating in the wrong direction, swap the two connections belonging to one of the motor coils.
Always turn off the power before changing motor connections, or you may destroy the motor driver.