int Rled = 8; // this led is connected to pin 8
int Yled = 7;
int Gled = 6;

void setup() {
pinMode(Rled, OUTPUT);
pinMode(Yled, OUTPUT);
pinMode(Gled, OUTPUT);
}

void loop() {
digitalWrite(Rled, HIGH);
digitalWrite(Yled, HIGH);
delay(3000);
digitalWrite(Yled, LOW);

digitalWrite(Gled, HIGH);
delay(2000);
digitalWrite(Gled, LOW);

}