Locating Files

You can download the library directly in the library manager of the Arduino IDE itself.

I can see Files, Sketch, Tools and Help at top. Can you point me in the right direction please.

What is :Sketch" anyway?

You may find the Arduino docs helpful. This one provides an introduction to Arduino development. https://www.arduino.cc/en/Guide/Environment

This one provides a step-by-step guide to installing third-party libraries like #lighthack. https://www.arduino.cc/en/Guide/Libraries

Great. Well on way now. Rather and odd thing. I downloaded IDE into my (defualt) "Downloads" folder. If I extracted there I could run the IDE .exe fine. Able to load the other files. But, kinda odd; If I copied the downloaded file to say "/My Docs/Arduino/" trying to excute would cause the IDE to pop open and then disappear a couple of seconds later!

I find the Arduino IDE that you can download from arduino.cc to work better than the Windows store version, as you can add support for teensy boards to the non-store version.  The Windows installer can be found at https://www.arduino.cc/download_handler.php?f=/arduino-1.8.10-windows.exe

As for the Arduino sketch, that's just fancy speak for uncompiled code.  The easiest way to get started is to copy the raw code on https://github.com/ETCLabs/lighthack/blob/master/box_1/box_1_src/box_1_src.ino and paste it into a blank sketch in Arduino IDE.   

Ok thanks. Well at this time I am up and running the test code with appropriate LEDs flashing and handshaking the EOS. I couldn't hack a clean plastic cover for the "box" so cut out an a aluminum one. It's not too bad but thought I wanted to make the really good looing and decided to pay for a 3D printed plastic face plate. Waitng delivery - soldering iron on stand by.

Ok thanks. Well at this time I am up and running the test code with appropriate LEDs flashing and handshaking the EOS. I couldn't hack a clean plastic cover for the "box" so cut out an a aluminum one. It's not too bad but thought I wanted to make the really good looing and decided to pay for a 3D printed plastic face plate. Waitng delivery - soldering iron on stand by.