match table to screen software (various)

Hi
My first question in this group is to find out how to make my screen layout match the actual table on the CNC laser.

I have a set of end-stop kit on their way from China.
I have to admit that I would rather like to get it working without the end stops first.

How do I do the correlation between table and screen?

I have watched some You-Tube items on this, but need the simplest explanation because I've tried to follow them but end up just the same.:hysterical: