Excellon_to_Gcode is a Python script to create Gcode from an Excellon file, in this case, generated by Eagle. Excellon file is just a file where you can see the coordinates of all your holes in a PCB, so in this way, a GNC machine can drill these holes. In the repository files, there is a manual(in Spanish) that shows how to generate the Excellon file in Eagle. All you have to do is:
You will see as many Gcode files as drill bits
In the repository files, you will find "drills.xln". This file is a short example of an Excellon file with 4 drill bits. Following the previous example, we generate the 4 Gcode files that you can find in the repository. Then, you can introduce, one by one, this Gcode.txt in your CNC machine and see the magic. In my case, I had an SRM20 CNC machine and worked perfectly.
A PCB is not complete without the traces, so I suggest you use this web where you can create traces files so your CNC do all for you #http://fabmodules.org/
Is a very simple page where you can introduce a black and white image of your PCB, choose your CNC machine, and it will generate the traces files for you to introduce in your CNC. After this, you will have prototyped your PCB in an easy way.
In the file section, you will find 4 images. PCB_inverted_pendulum corresponds to a PCB I designed for an inverted pendulum project. It is very poor welded(it was my first big project). The others correspond to the same project. It was a shield for a 4 relay board and an ESP8266. These 2 boards were drilled by this script in an SRM-20 Roland Machine.
Please, don't doubt to ask if you have any questions