To get help you can see the video.

Source code for signup page.

1. Insert code

First you need to insert value into the table then you show value in table.

try {
            if (jTextField_User.getText().equals("") || jTextField_lastName.getText().equals("") || 
                    jTextField_Email.getText().equals("") || jTextField_Age.getText().equals("")) {
                JOptionPane.showMessageDialog(null, "Fieldes Must Not be Empty...");
            } else {
                String query = "insert into user(f_name,l_name,email,gender,age,confermation) values(?,?,?,?,?,?)";
                pst = con.prepareStatement(query);
                pst.setString(1, jTextField_User.getText());
                pst.setString(2, jTextField_lastName.getText());
                pst.setString(3, jTextField_Email.getText());
                pst.setString(4, (String) jComboBox1.getSelectedItem());
                pst.setString(5, jTextField_Age.getText());
                pst.setString(6, conferm);
                pst.execute();
                JOptionPane.showMessageDialog(null, "Created Successfully..");
                showValueInTable();
            }

        } catch (HeadlessException | SQLException e) {
            JOptionPane.showMessageDialog(null, "Not Created...");
        }

2. show value in table.

public void showValueInTable(){
        try{
            String sql = "select * from user";
            pst = con.prepareStatement(sql);
            rs = pst.executeQuery();
            jTable1.setModel(DbUtils.resultSetToTableModel(rs));
        }catch(SQLException e){
            JOptionPane.showMessageDialog(null, e);
        }
    }

Interface of after run the signup page.