The Galileo was built to model how the Arduino accesses the outside world. Much of that access should be through the GPIO pins. The Galileo comes with a standard set of 14 digital and 6 analog IO pins, along with some additional pins to provide power and serial IO. Fortunately, the pins are actually well labeled on the board itself.
Here is a close-up:
Here is a list of pins that are available, and a brief description of what each pin can do, starting at the upper right and going clockwise. A more in-depth description of these pins will come later as you actually use them in some example projects:
