As you likely don’t need the enable or sleep pins I’d put a wire from the enable pin to ground (to make sure its low) or connect it to a Arduino output pin and set that low (but not both as that may damage the Arduino) and connect sleep to +5V with a 1K ohm resistor to make sure it is high. If it still doesn’t work you could check the voltages on the motor connections. If it isn’t stepping they should be stable and should be either ground (or close to it) or the motor supply voltage (possibly 12V?), if it is less than the supply voltage you are probably looking at current limiting and need to first check the wiring to make sure you don’t have a short and then increase the current limiting pot as the tutorial indicates until the driver is supplying enough current to run the motor.
Peter