my pong game

right now in intro to C++ we are developing games for our final but im havin some difficulties and i was hoping someone could give me some help. here is what i have soo far. the problem is i cant get my paddle to move when i run my applet

import java.awt.*;
import java.applet.*;
import java.lang.Thread;

public class Padle extends Applet implements Runnable{
     
     int yourPadle = 70;
     
     private Image dbImage;
     private Graphics dbg;
     private Thread th;
     
public void init() {
     setBackground (Color.black);
           th = new Thread(this);
     }
     
public void start (){            
           th.start();
     }
     
public void stop(){
           th.stop();
     }

public boolean keyDown(Event e, int key){
     if(key==Event.UP){
           yourPadle =- 7;
           }
           
     else if(key==Event.DOWN){
           yourPadle =+ 7;
           }
     return true;
     }
     
public void destroy(){
           th.stop();
     }
     
public void run(){
     
}

public void paint(Graphics g) {
     
           g.setColor(Color.white);
           g.fillRect(20,yourPadle,20,80);
     }
     
}