How to make a bullet in a top down arcade-styled game?

Hello! I am >18 and I like spending some time in Unity!

So this is my first game and i want to create a game based on the old arcade games where you are a spaceship and you try to make a highscore by killing alien spaceships. I hope you understand :P

I want a script where if i press "X", it will shoot a bullet (Which is a sprite) and on contact with the enemy it will kill him. I only want to know how to make the bullet shoot forward (Up in the Y axis)

Here is a quick script i made: (It may be completely wrong)

 var Bullet1 : Sprite;
 
 function Update()
 {
    if (GetButtonDown("Shoot1") {
       var ShootSound1 : AudioSource = GetComponent.<AudioSource>();
       ShootSound1.Play;
       //Here i want to tell Unity to spawn the Bullet1 sprite and move it only up, on the Y axis in a certain speed. let's say 10
 
 }
 }