Are you talking about this image:
It uses GPIO 16 for the LED and GPIO 4 for the button.
These are the GPIOs used in the code:
const int buttonPin = 4; // the number of the pushbutton pin
const int ledPin = 16; // the number of the LED pin
Or are you talking about something else?
Very confusing when you start unit 2 with a 30 pin version and in unit 7 you use the same pins but they are in a different place, because (without telling anybody) switched to the 36 pin version.