CNC read out to display

I have a Kuman 3.5 inch tft display sheild and an Arduino Uno, and an Arduino Mega. I would like to see my X,Y and Z displayed on this shield. I have a sheild with 4 A4988 drivers but I have a way to get to the pins that’s sending out that info or can I just use another board and plug the display on it and connect the two boards together. One the master and one the slave.

Thanks for any help anyone may have on this mater.