UP Squared (UP2) - How to use exHAT's GPIOs ?

Hello Everyone,
I am trying to use the ExHat-60 Pin (the simpliest use of it) of the Up2 and I am kind of lost on what I need to do to control any of those Pin and turn on a LED for example.
I found info there : https://wiki.up-community.org/Pinout_UP2 to be able to use the 40-Pin HAT (not tested yet) but it does not seems as easy to use the exHAT Connector. (or I didn't get how to use the exHAT Pinout array)
If anyone can point me the right direction on which file to modify to add the exHAT-60 Pin spec (an equivalent to a board.h ?) or the library to download to use the exHAT, it would be appreciated.
Also If anyone succeded on how to use the exHAT, I am interested on How you did it.
Thanks to all who read this.
Thom
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