Stacking motor shields

Projects General Guidance
1

I have heard that you can use two arduino rev3 motor shields. Also i heard that you have to modify the pins on one of the shield so that you can control them independantly. All i want to know is how to set this up?
Which pins do i connect? How do i connect them and which pins do i cut?

The adafruit motor shield is out of the question since for some reason it just doesnt work. It wont run my code at all and the motors I connect dont run except for.one that just constantly spins in one direction. I have asked about this on the adafruit forum but i have hit a dead end

2

Thx for all of your help. I think I am gonna buy a second arduino and two rev 3 motorshields and control 4 motors that way since it otherwise is just to stupid and unrefined for a noob to try