Confusion with pin mapping with arduino uno to keypad lcd display

Hello, I am quite new with working with Arduino and I recently got the keypad lcd display. I have the schematic of the pinout but something I am confused about is that it says D10 is responsible for adjusting the lcd backlight. I am attempting to include a potentiometer to adjust the brightness of the lcd display, but I am confused with what pin to use as I was essentially going to use the bottom part of the lcd board where gnd 5v and the input analogue pins are but the fact that D10 is said to be responsible for the backlight confused me and I am afraid to damage the board.

Also, I understand from the mapping that D10 on the Arduino corresponds to the 6th pin up from the left on the lcd but I am not sure how to connect to it as it has no input for a wire or anything. (basically unsure what to do with J1 and J2 to have access to the pins it corresponds to).

An explanation would be very appreciated, thank you!