I’ve tried to add some more details about the commands below.
The first thing you would do is place the touch plate on top of your stock.
This command tells the machine to move Z down until the Z-Min input is triggered. This is the input you connect the touch probe to.
This command tells the machine that Z is currently at a height of 10mm
G0 Z5 F480
This command moves the Z axis up 5mm so you can take the touch plate away.
The machine is now set so that the top of your stock is at Z0 so if you want to engrave 2mm you just tell Estlcam to go 2mm deep.
Hope this makes it clearer.