Use Composite design pattern to make a group of shapes be represented as objects

Im doing some school homework and came across this task. I don't really know how to do that with what I have done so far. This is my code.

    abstract class Shape {
         abstract void draw();
    }

    class Circle extends Shape{
        @Override
        void draw() {
            System.out.println("Drawing a circle");
        }
    }

    class Rectangle extends Shape{
        @Override
        void draw() {
            System.out.println("Drawing a rectangle");
        }
    }

And my main method

public static void main(String[] args)
{
    List<Shape> shape = new ArrayList<>();


    Shape [] shapes = new Shape[2];

    Rectangle rektangel = new Rectangle();
    Circle sirkel = new Circle();

    shape.add(rektangel);
    shape.add(sirkel);
 }