[hardwired]

how & where do i start?
There are many ways to do this. On possibility is shown below in pseudocode.
should i use packages?
Yes, you will need to import a few.
AWt? or SWING?
Swing is easier and more fun. The tutorial examples use Swing.
Application? or Applet???
Your choice. Applications are easy enough to start with. Some prefer applets.
how do i draw from input by clicking on buttons?
Say, for an application, you could put something like this together to get started.

Code:

public class MyClassName extends JPanel {
    JTextField textField;
    String text = "";

    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        float x = whereever
        float y = you prefer
        g.drawString(text, x, y);
    }

    private JPanel getNorth() {
        textField = new JTextField(numCols);
        // add this to a panel and
        return panel
    }

    private JPanel getButtonPanel() {
        JButton button = new JButton("your_string");
        button.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                text = textField.getText();
                repaint();
            }
        });
        // add the button to a JPanel and
        return panel;
    }

    public static void main(String[] args) {
        MyClassName app = new MyTestApp();
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.add(app.getNorth(), BorderLayout.NORTH);
        f.add(test);  // default center section
        f.add(test.getButtonPanel(), "South");
        f.setSize(...
        f.setLocation(...
        f.setVisible(true);
    }
}