I also have the same cutter.. if not using the barcode it means what you see in this photo.
View attachment 182355
if you are using the barcode you would be about 1.5" to the left of this position and the barcode would be FURTHER BACK into the machine by about 1"
the Tool is the holder you are using.. 99% of the time would be the drag knife but you could be using a scorer or pen or .... so they call it the "tool" and the "first mark" is the first mark as close to the control panel as possible depending on which roller setup you are using.