Stepoko: Powered by grbl Hookup Guide
Contributors:
MTaylor
MTaylor 
Software and Firmware Overview
Milling is a little more interactive than just sending a job to a printer. After the hours put into modeling, the model files are converted into what's called G-code by CAM software. Then, the G-code is sent to the mill by some machine control software (in our case, universal G-code sender). The mill itself runs firmware which can interpret what the machine control software is saying and in turn, drives the stepper motors to move the mill. Whew.
This process of walking through various programs is know as a tool chain. This graphic shows each distinct part of the tool chain, though the machine firmware is not usually talked about, and sometimes (in particular for 3D printing) the CAM and gcode sending software are the same.
The solid modeling, design work, and CAM software are not in the scope of this hookup guide, and from here on it is assumed that you have some gcode from somewhere. Several examples exist in the Stepoko github including a 1x1 inch square, a few 10x10 inch squares, and the SparkFun flame.