My machine (basically this build: https://www.thingiverse.com/thing:1514145) has GRBL 0.9 : https://github.com/grbl/grbl/wiki/Configuring-Grbl-v0.9 The documents for newer version are up there too, obviously. It would definitely be good to get v1.1 working in order to learn the process of getting it on a fresh Arduino board. I'll outline the process of how to do that in the section below this one and fill in the details as I get around to figuring them out. Here's what I do know for sure though...
You can use any number of GUIs but the premise is always the same.
Once the firmware is on your board, connect it via USB, power it on, and search in your /dev/
directory for your Arduino (type that into Terminal and start typing "tty" and then hit Tab until something shows up). If you have the Arduino software, use the drop down menus to identify an address like /dev/ttyusb####
or /dev/wchusbserial####
The numbers will be u