Apologize for the basic questions but where are the functions that are in the screen load script stored?  I am not sure how to add or modify functions that are in there.  Bonus if you can point me to a resource where I can learn more.  The documentation for LUA programming in the Mach4 manuals didn’t quite work for me.

Go to 'operator->edit screen' then in the screen tree manager panel click on the top most entry(screen name), then in the properties panel click on the second icon which shows a list of scripts, click on the Screen Load Script.
HTH
RT

I got that far but you cannot modify and save anything here.  Or at least I couldn’t.

Did you click on the three ellipses in the second column?  That brings up the editable script.

I am not a programmer and had problems starting also.
I made this and it might help you also.

https://www.machsupport.com/forum/index.php?topic=45397.msg289143#msg289143

Bill