Hey Keith,
you got to set your real workpiece’s workpiece zero exactly where it is located in your virtual 3D model. This is the way you ensure that your CNC machine knows where the workpiece is. So if you have the zero coordinate (“model origin”) at the center in your virtual 3D model, you got to make sure you probe or manualy set the workpiece zero also exactly at the center of the real workpiece. But If you have the zero coordinate on the top front left corner of your 3D model, you got to probe or manually set the workpiece zero on the top front left corner of the real workpiece too.
The machine will assume that this way you show it where it is, as otherwise the machine wouldn’t know where it is in relation to the real workpiece.