When I was creating my PiGrrl Zero plus with sound I had several helpful documents that I made to map out the pins on the GPIO.
I was cleaning up files on my computer and before I deleted them I wanted to post them.
The picture below is the mapping of a RaspberryPi B board.
This is the wiring setup for the PiGRRL Zero Plus board.
This is a diagram I created to help easily wire everything to the GPIO.