Homework Help - simple calendar with adding simple events

Hi can I ask for some help regarding my homework.

I need to make simple calendar with the ability to add some simple events/reminders/notes to it.

I got written calendar:

import java.awt.*;
import java.awt.event.*;
import java.util.*;

public class Jakub extends Frame {
	Choice miesiąc;
	Choice rok;
	Button dni[] = new Button[49];
	Button start = new Button("Start");

	Label lmiesiąc;
	Label lrok;

	int dzisiaj;
	private static final int[] leapYearDays = { 31, 29, 31, 30, 31, 30, 31, 31,
			30, 31, 30, 31 };
	private static final int[] regYearDays = { 31, 28, 31, 30, 31, 30, 31, 31,
			30, 31, 30, 31 };

	Panel p1, p2;
	GregorianCalendar gc;

	public void setCal(int selMonth, int selYr) {
		int selYear = selYr - 1900;
		Date d1 = new Date(selYear, selMonth, 1);
		int day = d1.getDay();
		miesiąc.select(selMonth);
		rok.select(selYear);
		setVal(d1, day, selMonth, selYear);
	}

	private void createMonthYear() {
		Font f = new Font("ScanSerif", Font.BOLD, 11);
		gc = new GregorianCalendar();
		miesiąc = new Choice();
		rok = new Choice();
		lmiesiąc = new Label("Miesiąc");
		lrok = new Label("Rok");
		lmiesiąc.setFont(f);
		lrok.setFont(f);

		miesiąc.add("Styczeń");
		miesiąc.add("Luty");
		miesiąc.add("Marzec");
		miesiąc.add("Kwiecień");
		miesiąc.add("Maj");
		miesiąc.add("Czerwiec");
		miesiąc.add("Lipiec");
		miesiąc.add("Sierpień");
		miesiąc.add("Wrzesień");
		miesiąc.add("Październik");
		miesiąc.add("Listopad");
		miesiąc.add("Grudzień");

		for (int i = 1900; i < 3000; i++) {
			rok.add(String.valueOf(i));
		}
		rok.addItemListener(new myLis1(this));
		miesiąc.addItemListener(new myLis1(this));
	}

	public Jakub() {
		Frame f = new Frame();
		setTitle("Kalendarz");
		setSize(500, 500);
		setResizable(false);
		setLocation(50, 50);
		p1 = new Panel(new FlowLayout(FlowLayout.LEFT));
		p2 = new Panel(new GridLayout(7, 7, 10, 10));
		p1.setBackground(Color.blue);
		p2.setBackground(Color.red);
		add(p1, BorderLayout.NORTH);
		add(p2);

		createMonthYear();

		p1.add(lmiesiąc);
		p1.add(miesiąc);
		p1.add(new Panel());
		p1.add(lrok);
		p1.add(rok);
		p1.add(new Panel());
		p1.add(start);

		start.addActionListener(new myLis(this));

		for (int i = 0; i < 49; i++) {
			dni[i] = new Button("");

		}

		for (int c = 0; c < 49; c++) {
			p2.add(dni[c]);
		}
		setVisible(true);

		Calendar rightNow = Calendar.getInstance();
		int selMonth = rightNow.get(Calendar.MONTH);
		int selYear1 = rightNow.get(Calendar.YEAR);
		setCal(selMonth, selYear1);
		this.addWindowListener(new WindowAdapter() {
			public void windowClosing(WindowEvent e) {
				System.exit(0);
			}
		});

	}

	void setButtons(int myday, int mytotdays) {
		int count = 7;
		Font f = new Font("Helvetica", Font.BOLD, 30);

		dni[0].setLabel("Pn");
		dni[1].setLabel("Wt");
		dni[2].setLabel("Śr");
		dni[3].setLabel("Cz");
		dni[4].setLabel("Pt");
		dni[5].setLabel("So");
		dni[6].setLabel("N");

		for (int i = 0; i < 7; i++) {
			dni[i].setFont(f);
		}

		dni[0].setForeground(Color.RED);

		if (myday > 0) {
			int blank = myday;
			for (; blank > 0; blank--, count++) {
				dni[count].setLabel("");
			}
		}
		for (int i = 1; i <= mytotdays; i++, count++) {
			dni[count].setLabel("" + i);

			dni[count].setFont(f);
			if (count == 7 || count == 14 || count == 21 || count == 28
					|| count == 35 || count == 49)
				dni[count].setForeground(Color.RED);
			else
				dni[count].setForeground(Color.BLACK);
		}
		for (int j = 1; count < 49; j++, count++) {
			dni[count].setLabel("");

		}
	}

	void setVal(Date date, int iday, int iselMonth, int iselYear) {
		gc.setTime(date);
		if (gc.isLeapYear(iselYear))
			dzisiaj = leapYearDays[iselMonth];
		else
			dzisiaj = regYearDays[iselMonth];

		setButtons(iday, dzisiaj);
	}

	static public void main(String args[]) {
		Jakub c = new Jakub();
	}
}

class myLis implements ActionListener {
	Jakub calLis;

	public myLis(Jakub c) {
		calLis = c;
	}

	public void actionPerformed(ActionEvent i) {
		int selMonth = calLis.miesiąc.getSelectedIndex();
		int selYear1 = Integer.parseInt(calLis.rok.getSelectedItem());
		int selYear = selYear1 - 1900;
		Date d1 = new Date(selYear, selMonth, 1);
		int day = d1.getDay();
		calLis.setVal(d1, day, selMonth, selYear);
	}
}

class myLis1 implements ItemListener {
	Jakub calLis;

	public myLis1(Jakub c) {
		calLis = c;
	}

	public void itemStateChanged(ItemEvent i) {
		for (int k = 7; k < 49; k++) {
			calLis.dni[k].setLabel("");

		}

	}
}

Now what I would like to achieve is to click particular button with date and then open new window with simple texbox to add some note and save it.

How should I write code for clicking and opening new window?

Also should I use serialization to save those newly added notes?

I don't need any savings to file or database just simple let say array to hold let say 10 new events.

Can I ask you for some help?