Programming enemies

Here is the code to paste in the enemy0:
onClipEvent(load)
{
function reset()
{
var timer = 12;
this.y = Math.random() * 300
this.x = 550
mySpeed = Math.ceil(Math.random() * 6) + 1;
}
reset();
}
onClipEvent(enterFrame)
{
//in every frame the enemy move left in the speed defined in the reset function.
this.x -= mySpeed;
if (this.x < -10)
{
//if the enemy is not on the screen, we reset it.
reset();
}
//if our timer is bigger than 12 we get a new
if (timer >= 12)
{
//direction to the Ship.
var dir = Math.ceil(Math.random() * 2)
//We get a random number, 1 or 2. 1 is up, 2 is down.
//Then we set timer to 0, so we only get a new dir when timer is bigger than 12
timer = 0;
}
if (dir == 1)
{
//if dir = 1, we move the ship up.
this.y -= 3;
} else if(dir == 2)
{
//if dir = 2, we move the ship down.
this.y = 3;
}
//increase timer by 1, so the timer gets equal to 12 and we get a new direction.
timer+
}

This is the code to paste in the main timeline:
var nrEnemies = 3;
for (i = 1; i < nrEnemies; i++)
{
_root.Enemy.duplicateMovieClip(“Enemy” + i, _root.getNextHighestDepth());
}