Yes, I found the schematics - I have attached it.
That's more like a wiring diagram than a schematic (regardless of how they name the file).
I was trying to figure out how to access the Arduino pins through the shield, therefore I make a sketch that makes a led on digital pin 3 blink.
According to that diagram, near the upper left corner, Arduino digital pin 3 (D3) is connected to pin 4 of J5 on the shield.
... don't you need the PCB layout to see that?
A photo of the shield might provide the information.
Don