Hello, you can read the pin picture here:Getting Started | Seeed Studio Wiki, the name of pin is here: if you wanna use the pin D2, you can see D2 match the GPIO3, so you can use it by “IO3”, such as machine.Pin(IO3,machine.Pin.OUT) or two lines like:
machine_pin= digitalio.DigitalInOut(board.IO3)
machine_pin.direction = digitalio.Direction.OUTPUT