thing/TwoPlayerGameDriver

import javax.swing.*;
import java.awt.*;

public class TwoPlayerGameDriver
{
    public static void main(String[] args)
    {
        JFrame frame = new JFrame();
        frame.setTitle("Two Player Game");

        // CardLayout
        CardLayout layout = new CardLayout();
        JPanel container = new JPanel(layout);

        //Panels
        GameFields gamePanel = new GameFields();
        LvlManager levelMenu = new LvlManager(gamePanel);
        MainMenu menuPanel = new MainMenu(gamePanel);

        //add to cardLayout
        container.add(menuPanel, "MENU"); //+ more
        container.add(levelMenu, "LEVELS");
        container.add(gamePanel, "GAME");

        //switch screens
        menuPanel.setContainer(container,layout); //+ more
        levelMenu.setContainer(container,layout);
        gamePanel.setContainer(container,layout);

        frame.add(container);
        frame.pack();
        frame.setLocationRelativeTo(null);
        //gamePanel.requestFocus();
        frame.setVisible(true);

        //frame
        frame.setResizable(false);
        frame.setSize(640, 360); //<-- change later
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }
}