Here's the header pinout: http://www.cnx-software.com/2015/09/26/status-of-orange-pi-boards-gpio-support/
Here's the steps: https://linux-sunxi.org/GPIO
So, to up pin 12, a.k.a. PD14 I do:
echo 110 > /sys/class/gpio/export
echo "out" > /sys/class/gpio/gpio110/direction
echo "1" > /sys/class/gpio/gpio110/value
