Whether you have a C.H.I.P. Pro on the dev board or bare, learn how to access the GPIOs pins through sysfs on the C.H.I.P. Pro documentation page. You can also find a pinout diagram and the pin descriptions on the doc page and datasheets on our GitHub.
The Dev Kit board has some hardware and pins broken out, make sure to check out what's on the dev board on out C.H.I.P. Pro Dev Kit documentation page.