Light up an LED (light-emitting diode)

1. Refer to the GPIO (General-purpose input/output) location of Raspberry Pi 2 Model B:
Below image is from: https://www.raspberrypi.org/documentation/usage/gpio-plus-and-raspi2/README.md

2. Refer to the breadboard internal connection.
Below image is from: http://whitelinetracer.page.tl/Details-of-Components--d--Page1.htm

3. Connect the 3.3V and ground pins to a breadboard.

4. Connect the longer leg / pin of the LED (called the anode) to the 3.3V voltage supply.

5. Connect one pin of a resistor to the shorter leg / pin of the LED (called the cathode), and the other pin of the resistor to the ground.

6. The LED should light up as the photo below: