This is a very simple starter program for Arduino beginners. It is commonly called blink. It does what the title says it does: it makes a LED (any color) blink!

Materials you will need:

Arduino (I have the Uno, and am using it)
Connection cord (From Arduino to computer)
LED (Mine is red)

Step 1:

Connect connecting cord to port on Arduino, then to computers USB port.

Step 2: Code

Here is the code For the program. Put it into your Arduino program.

int led = 13;

void setup() {
pinMode(led, OUTPUT);
}

void loop() {
digitalWrite(led, HIGH);
delay(1000);
digitalWrite(led, LOW);
delay(1000);
}

Step 3:

Plug the LED into the 13 pin on the digital side, and the other leg into ground. If everything goes right, the LED will blink on and off!

Note: Some Arduino models have a built in LED on the board.