GridBagLayout help

I may just be totally misusing GridBagLayout, but, given the tutorials I have read, I don't understand how I might be.

The code is:

Code Java:

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
 
public class ButtonsGUI extends JFrame
{
    JButton button;
    JLabel label = new JLabel("No buttons clicked");
    Flash flash;
    ActionListener bl;
 
 
    ButtonsGUI()
    {
        setSize(275, 275);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setVisible(true);
 
        setLayout(new GridBagLayout());
        GridBagConstraints con = new GridBagConstraints();
 
        bl = new ButtonsListener(this);
 
        //flash = new Flash(label);
 
        con.gridx = 0;
        con.gridy = 0;
        con.gridwidth = 2;
        add(label);
 
        button = new JButton("Left");
        con.gridx = 0;
        con.gridy = 1;
        con.gridwidth = 1;
        button.addActionListener(bl);
        add(button);
 
        button = new JButton("Right");
        con.gridx = 1;
        con.gridy = 1;
        con.gridwidth = 1;
        button.addActionListener(bl);
        add(button);
    }
}
 
class ButtonsListener implements ActionListener
{
    String butStr;
    String labStr;
    String newStr;
    JLabel lab;
 
    ButtonsListener(ButtonsGUI bg)
    {
        lab = bg.label;
    }
 
    public void actionPerformed(ActionEvent ae)
    {
        butStr = ae.getActionCommand();
        labStr = lab.getText();
 
        if (labStr.equals("No buttons clicked"))
        {
            newStr = labStr.substring(2, 9) + labStr.substring(10, 18);
 
            if (butStr.equals("Left"))
            {
                lab.setText(butStr + newStr);
            }
            else if (butStr.equals("Right"))
            {
                lab.setText(butStr + newStr);
            }
        }
        else if (labStr.equals("Left button clicked"))
        {
            newStr = labStr.substring(4, 19);
 
            if (butStr.equals("Right"))
            {
                lab.setText(butStr + newStr);
            }
        }
        if (labStr.equals("Right button clicked"))
        {
            newStr = labStr.substring(5, 20);
 
            if (butStr.equals("Left"))
            {
                lab.setText(butStr + newStr);
            }
        }
 
    }    
}
 
class Buttons
{
    public static void main(String args[])
    {
        new ButtonsGUI();
    }
}

Currently, all the elements are displaying in the same row. I thought that I had correctly used the constraints to specify column and row, but, apparently, I don't know how to specify constraints.