How do I transfer the user from one jframe to another jframe?

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class MainFrame extends JFrame {
    private CardLayout cardLayout;
    private JPanel cardPanel;

    public MainFrame() {
        setTitle("Login App");
        setSize(400, 300);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        //Create the CardLayout Method...
        cardLayout = new CardLayout();
        cardPanel = new JPanel(cardLayout);

        //Create and add your login panel...
        JPanel loginPanel = createLoginPanel();
        cardPanel.add(loginPanel, "login");

        //Create and add your next page panel...
        JPanel nextPagePanel = createNextPagePanel();
        cardPanel.add(nextPagePanel, "nextPage");

        add(cardPanel);

        //Create a button to switch to the next page...
        JButton nextPageButton = new JButton("Go to Next Page");
        nextPageButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                cardLayout.show(cardPanel, "nextPage");
            }
        });

        //Add the button to the login panel...
        loginPanel.add(nextPageButton);
    }

    private JPanel createLoginPanel() {
        JPanel loginPanel = new JPanel();
        //Add your login components here...
        return loginPanel;
    }

    private JPanel createNextPagePanel() {
        JPanel nextPagePanel = new JPanel();
        //Add components for the next page here...
        return nextPagePanel;
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                new MainFrame().setVisible(true);
            }
        });
    }
}