you follow the shield's instructions or datasheet for wiring it up.  if you can't find any, buy a different one, or from a supplier that gives you the instructions.

I'm modding my Ender 3 3D printer and need to drive a [40mm stepper motor](https://www.amazon.com/Stepper-Motor-Bipolar-64oz-Printer/dp/B00PNEQI7W/).  I found [this shield](https://www.amazon.com/gp/product/B00RCTW5SM) that appears to be compatible with it.

Would I need to supply voltage externally?  My plan is to pull 12V from the printer's PSU to power the Arduino board if I can find a tap.  Otherwise I can get a wall-wart for that.

How would I wire up and control a 40mm stepper motor?