SainSmart "Blue" Breakout Board

I have one of these boards and when you combine it with a stepper driver it controls stepper motors very well thru Mach 3. I am trying to figure out how to exactly wire the E-stop. There are directions but they don't seem to work. My question is, does anyone else have this board and have they hooked up an e-stop properly and how ???

Thanks Steven
View attachment 10624