Help with point system?

I am making a shooting game. But I don't know what code to use to display score.

This is the entire script

var sfx_gun:Sound = new sfx();
var sp:MovieClip = new ship();
var tm:Timer = new Timer(1500);

tm.addEventListener(TimerEvent.TIMER, onstart);

var bulletholder:Sprite = new Sprite();

addChild(bulletholder);

addChild(sp);

addEventListener(Event.ENTER_FRAME,onenter);
stage.addEventListener(MouseEvent.CLICK,onclick);

tm.start();
function onstart(e:Event){
   
   
    var em:Sprite = new enemy();
    em.x= Math.random()*550;
    addChild(em);
   
   
    }

function onenter(e:Event):void {
    sp.x-=(sp.x-mouseX)*.1;
    sp.y-=(sp.y-350)*.2;
}

function onclick(e:Event) {
    sfx_gun.play();
    sp.y=365;
    var bl:Sprite = new bullet();
    bl.y=sp.y;
    bl.x=sp.x;
    bulletholder.addChild(bl);
}

ship is the ship

sfx is the gunshot sound

enemy is the target

bullet is the bullet

If you need more info please reply