Code for the blinking LED:
void setup()
{
pinMode(13, OUTPUT);
pinMode(12, OUTPUT);
pinMode(11, OUTPUT);
pinMode(10, OUTPUT);
}

void loop()
{
digitalWrite(13, HIGH);
delay(500); // Wait for 500 millisecond(s)
digitalWrite(13, LOW);
delay(500); // Wait for 500 millisecond(s)
digitalWrite(12, HIGH);
delay(500); // Wait for 500 millisecond(s)
digitalWrite(12, LOW);
delay(500); // Wait for 500 millisecond(s)
digitalWrite(11, HIGH);
delay(500); // Wait for 500 millisecond(s)
digitalWrite(11, LOW);
delay(500); // Wait for 500 millisecond(s)
digitalWrite(10, HIGH);
delay(500); // Wait for 500 millisecond(s)
digitalWrite(10, LOW);
delay(500); // Wait for 500 millisecond(s)

}