Simulation - Two Cars Are Going To Race Against Each Other

I was thinking to make a game where two cars are going to race against each other. I already have two gif pictures which are the cars. I do now have a background and a racer track. So we can start from here.

I have made a object with construction which I called Racers. Inside that, i wrote a PaintWindow (Where the window and much more is inside), -car1, -car2. All these is private. So I made something like this now:

package p2;
public class Race {
private Object window;
private Car car1;
private Car car2;
public Race(PaintWindow window, Car c1, Car c2) {

[Code] .....

But the problem is now that im kinda lost and I dont really know what to write anymore. How can I get a for example a green background on the whole PaintWindow with two Racers tracks and inside the racers tracks (Each car have each track) does it have to be cars. So I need to somehow import the cars inside it too. But thats the problem I need. that I dont really know what more to do. To make it easier, I have a Main-method in another class.

public static void main(String[] args) {
PaintWindow window = new PaintWindow();
Car c1 = new Car(new ImageIcon("C:/Users/Sarah/Desktop/CarBlue.GIF"));
Car c2 = new Car(new ImageIcon("C:Users/Sarah/Desktop/CarRed.GIF"));
Race race = new Race(window,c1,c2);
race.action();
if(args.length>0) {
Paintwindow.pause(2000);
window.dispose();