Make an arduino fire alarm

I have got the flame sensor and the monitoring, but if a fire is detected, how do I make it sound in a Code-3 pattern (as in a real fire alarm system or a smoke alarm) and flash the LED very shortly every second?

What is a Code-3 pattern ?

Can you read the flame sensor ?
If so, then please post your code and details of the sensor

int relay = 4 ;// define relay pin
int flamedigital = 9; // define the flame sensor digital pin
int flameanalog = A3; // define the flame sensor analog pin
int buzzer = 11; //define buzzer pin
int val ; // define numeric variable val
float sensor; //define floating variable sensor

void setup ()
{
  pinMode (flamedigital, INPUT) ;// input interface defines the flame sensor
  pinMode (flameanalog, INPUT) ;// input interface defines the flame sensor
  pinMode (relay, OUTPUT); //output interface defines the relay
  pinMode (buzzer, OUTPUT); //output interface defines the buzzer
}

void loop ()
{
  sensor = analogRead(flameanalog); //read flameanalog value and assigne it to sensor variable


  val = digitalRead (flamedigital) ;// read flamedigital value and assigne it to val variable
  if (val == HIGH) // When the flame sensor detects a signal relay is on and buzzer sound (void alarm)
  {
    alarm();
    digitalWrite (relay, HIGH); //close the relay circuit

  }
  else
  {
    digitalWrite (relay, LOW); //open the relay circuit
  }
  delay(1000);
}

void alarm()  {
  //code 3 buzzer pattern
}

Sensor: Adafruit flame sensor
The Code-3 pattern is the sound a smoke alarm makes when it goes off.

Sorry, but I have no idea what a US fire alarm sounds like. Which device are you going to use to make the sound ?

Code 3 sounds like this.
I am using a buzzer.