Want to learn G-Code

I would like to learn everything there is about G-Code , I'm a retired electronic Eng and I need some good sources to learn G-Code I tried to understand GRBL while at the same time playing with U.G.S. but I guess this old dog can't be taught new tricks .I have a home built H-Frame C.N.C. which is 75" square ,without understanding why I'm getting errors is like chasing my tail .So please any insight as to where I can get information to understanding code would be appreciated .

Thank you ;)

Please pick your forum section a little more carefully Roger.

Not sure if you have READ THIS but i would suggest you do. It will help you get the best out of the forum and avoid the ire of other users.

Bob.

Search: "numerical control", one hit: https://en.wikipedia.org/wiki/History_of_numerical_control

Go to http://linuxcnc.org and read the tutorials, reference ....

What are the errors? Can you copy them and post here?