int ledPin = D3;

void setup() {

   pinMode(ledPin, OUTPUT);
   
}

void loop() {
    
    for(int i=0; i<5; i+=1){ //int starts at 0, increases by 1 at each loop, until it is at 5
        
        digitalWrite(ledPin, HIGH);
        delay(500);
        
        digitalWrite(ledPin, LOW);
        delay(500);
    }
    
    delay(3000); //waits 3 seconds
 

}