How do I get my spaceship to rotate

I’m creating a space shooter and I need my space ship to be able to rotate ,like a car just up and down as-well, when I press an arrow key(W/up d/right…etc) in-case you need it here’s my move script.

#pragma strict

var accelSpeed = 0.1;
var speed : float;
var dir : Vector2;


function Update(){
  transform.position += dir.normalized * speed;
if(Input.GetButton("Jump")){  
  
  AddSpeed();
  }else{
  
   SubSpeed();
  
  }
  
  if(speed < 0 ){
  speed = 0;
  }
  if(speed > 8 ){
  speed = 8;
  }
}

function AddSpeed(){
  speed = speed + accelSpeed;
  }
  
function SubSpeed(){

  speed = speed - (accelSpeed / 2);

}

thanks in advanced

var turn : float = Input.GetAxis(“Horizontal”)*turnSpeed;

transform.Rotate(0,turn,0);

This is what I use. turnSpeed is a variable dictating how fast you can turn. However it only works for me when it is the only rotational movement I am doing. Change the input however you like.