Ok, the data sheet for those motors is here (the S is single shaft, B = double shaft)

With those motors & driver you have the option to run them wired bipolar series at 2A or bipolar parallel at 2.5A (which is the limit of the driver, not the motor)

To run them in bipolar series, you need to join blue to red/white, use blue/white = 1A, red = 1B, join green to black/white, use green/white = 2A, black = 2B

To run bipolar 1A = Red+Blue, 1B = red/white + blue/white, 2A = green + black, 2B = green/white + black/white