My First Arduino Program

app.ino

void setup()
{
    // Configure the LED pin
    pinMode(LED_BUILTIN, OUTPUT);
}

void loop()
{
    // Set the PIN to 'high'
    digitalWrite(LED_BUILTIN, HIGH);
    // Wait 1 second (1000ms)
    delay(1000);
    // Set the PIN to 'low'
    digitalWrite(LED_BUILTIN, LOW);
    // Wait again
    delay(1000);
}