Java Swing openning a new button with components in another file
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I wrote the code for a basic Java Swing window and now I want to run a game in another window. The window is basically temporarily until the user hits the button. This is the code for the first window:

        import javax.swing.*;
    
    public class Main extends Game {
    	public static int height = 300;
    	public static int width = 200;
    	public String x = "X", y = "Y", player1, player2;
    	public String[] grid;
    
    	public static void main(String args[]) {
    /*--------------------------- DECLARATIONS ----------------------------*/
    		JFrame sudwin = new JFrame("Tic tac toe");
    		JLabel label1 = new JLabel("<html><b>Welcome to Tic Tac Toe!</b></html>");	
    		JLabel label2 = new JLabel("Player 1:");
    		JLabel label3 = new JLabel("Player 2:");
    		JLabel label4 = new JLabel("<html>Enter your names in the boxes, then </br>" + "click the start button to begin!</html>");
    		JLabel label5 = new JLabel("Version 0.1");
    		JTextField np1 = new JTextField();
    		JTextField np2 = new JTextField();
    		JButton btstart = new JButton("Start");
    		
    		sudwin.getContentPane().add(label1);
    		sudwin.getContentPane().add(label2);
    		sudwin.getContentPane().add(label3);
    		sudwin.getContentPane().add(label4);
    		sudwin.getContentPane().add(np1);
    		sudwin.getContentPane().add(np2);
    		sudwin.getContentPane().add(btstart);
    		sudwin.getContentPane().add(label5);
    /*--------------------------- METHODS ---------------------------------*/
    		sudwin.setSize(width, height);
    		sudwin.setVisible(true);
    		sudwin.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    		sudwin.setLocationRelativeTo(null);
    		sudwin.getContentPane().setLayout(null);
    		
    		label1.setBounds(26, 11, 156, 14);
    		label2.setBounds(10, 102, 100, 10);
    		label3.setBounds(10, 144, 100, 10);
    		label4.setBounds(10, 39, 172, 52);
    		label5.setBounds(10, 241, 100, 14);
    		np1.setBounds(10, 113, 111, 20);
    		np2.setBounds(10, 156, 111, 20);
    		btstart.setBounds(50, 202, 100, 28);
    		
    		btstart.addActionListener(new act1());
        }
    /*--------------------------- EVENT HANDLERS ----------------------------*/
    	static class act1 implements ActionListener {
    		public void actionPerformed(ActionEvent e) {
    			
    		}
    	}
    }

Basically, I have 2 java files: Main.java and Game.java

Main.java has the code above, which executes perfectly and Game.Java has the Jlabels and the JFrame but it is, by default, invisible. How can I make Main.java recognise all declarations from Game.java and make it visible when clicking the button? I'm on windows XP, using Eclipse.