gSender 1.1.2 autozero Touch plate to probe in top corners

Hi, new to cnc. I have a mk2 and trying to cut a 75 inc long by 15 w board. So the cut is on top (or back). I can not make the AutoZero Touch Plate to probe on the top left corner.
The cut start at the top of the board (finger joint).
If I can not probe at the top corner, what are the step to manually make the MK2 start at this point? (without the AutoZero Touch plate).

Note: searching, people have use a Macro to probe, but I think with the old Touch Plate (I only have the new one).
Thanks in Advance. Ralph