My home made cnc router

[cncksy]

Hi, I,m beginer build cnc router X axis 65" Y azis 25" Z axis 6", use Artcam and Mach3 softwear, cnc controller use 4 axis Kit.
I have problem is I don't know how to setup Zaxis auto zero I use input pin 11
???? ....

Sunny Yuen