CNC Router Part 4: Electronics & Software

Hey guys, here is Part 4 of my CNC Router Build. In part 4 I install the electronics and show the software I am using. Enjoy!
https://youtu.be/6shh4c_5YgQ

I do not understand the CNC Arduino connection, it looks to be completely separate from the motor drivers.

So basically my laptop controls the arduino output terminals (through universal gcode sender). And those output terminals connect and control the TB6600 Stepper Motor Driver. Which then controls the stepper motors. I used a cnc shield which makes it easier to pinout each output terminal (it plugs into the arduino). If you still don't understand I have 2 videos that explain the universal gcode sender program which is controlling the arduino. Hopefully this helped.