void setup() {
  // put your setup code here, to run once:
pinMode(10,OUTPUT); //set pin 10 (LED +) to OUTPUT mode
}

void loop() {
  // put your main code here, to run repeatedly:
digitalWrite(10,HIGH); //start outputting HIGH (+5V) on pin D10
delay(1000); //wait 1000 milliseconds (= 1 second)
digitalWrite(10,LOW); //start outputting LOW (0V) on pin D10
delay(1000); //wait 1000 milliseconds (= 1 second)
}