How to display or move sprite in as3 side scroller? - actionscript-3

Question

I have a sprite in my library called myRocket but it won't show up.
I made my sprite a movie clip then I deleted it off the actual page so it was just in the library. I thought using this code, the sprite would appear once I started up the game but it does not.
import flash.display.MovieClip;
stop() ;
removeChild(myButton);
var myReturn:Return=new Return();
addChild(myReturn);
myReturn.x=390;
myReturn.y=10;
myReturn.addEventListener(MouseEvent.CLICK, return1Function);
var up:Boolean;
var down:Boolean;
var left:Boolean;
var right:Boolean;
var speed:int;
function return1Function(evt:MouseEvent):void{
gotoAndStop("menu");
}
var myRocket:MovieClip;
addChild(myRocket);
myRocket.x=200;
myRocket.y=150;
function KeyboardDemo() {
myRocket.x = 200;
myRocket.y = 100;
addChild(myRocket);
stage.addEventListener(KeyboardEvent.KEY_DOWN, keyPressedDown);
}
function keyPressedDown(event:KeyboardEvent):void {
var key:uint = event.keyCode;
var step:uint = 5
switch (key) {
case Keyboard.LEFT :
myRocket.x -= step;
break;
case Keyboard.RIGHT :
myRocket.x += step;
break;
case Keyboard.UP :
myRocket.y -= step;
break;
case Keyboard.DOWN :
myRocket.y += step;
break;
}
}

Answer 1

You need to initialize your object before you place it to the stage. You have only declared a variable at the line "var myRocket:MovieClip;" instead it should at least (not sure about whatever logic you have there" read like above with "Return" whatever it was: var myRocket:MovieClip=new Rocket(); Here "Rocket" is the library name of the sprite.