I am extremely amateur when it comes to g code and what to add at the start.
I am using Estlcam 11 and looking to set it up so that once I have moved the LR3 into the right spot I can use the Z touch plate (mine is pictured below) to get the router bit to the correct height.
Do I need to include anything due to the thickness of the touch plate? In my head it would be the narrative of - z down on the touch plate. stop. raise by 5mm to clear the material and then start at a depth of the pass + 5mm + the depth of the touch plate
When you probe (after your Z38.2 Z0 and before you lift Z), send a G92 Z(x) where (x) is the thickness of your probe in mm (For a 0.5mm probe, send G92 Z0.5).
That will set the top of the stock to Z=0, and all subsequent Z commands in gcode will use that as a reference.
What you send depends on what control board you are using. I would suggest using the link below and selecting the correct control board and using the start g-code script suggested.