I there a tutorial on hooking up a Z axis zero touch plate to the usb controller?

To use a touch plate on any controller, all you need is a conductive flat material with a known thickness and some wire and alligator clips. Solder a wire to the touch plate and connect the other end of the wire to the free input terminal of the controller. Connect a wire with an alligator clip to the ground of the controller (on the Mach3 USB controller, this ground is the DCM terminal, or the digital gnd on the 24VDC power supply). Connect the alligator clip to the end mill. You can either use a script to serve as the probe, or you can use the ref all home button and setup the touch plate as a home switch.