New to Java

Hello,
Im very new to java and in fact im taking it in a computer course from my university. Im having great difficulties with some of the things i have to do. I need to create new objects and i just dont know how to. I have tried several times on my own but i get errors when i compile or it just dosent work. I need to create circles, semi-circles and triangles. This is the code that was give to me to use:

/**
* Part 0
* Circle and semicircle
*/

import java.awt.*;
import java.applet.*;

public class Part0 extends Applet {

// Instance variables
// Image location.
// Diameter of each shape.
// Colour of each shape.
// Angles for the semicircle.

private Location imageLocation;
private Angles angles;
private int semiDiameter;
private int circleDiameter;
private Color circleColor;
private Color semiColor;
private Location semiOffset;
private Location circleOffset;
private ColouredSemiCircle semi;
private ColouredCircle circle;

/**
* Initialize the variables needed to
* describe the two shapes.
*/
public void init() {

imageLocation = new Location(50, 100);
semiOffset = new Location(0, 0);
circleOffset = new Location(-30, 50);
circleDiameter = 100;
semiDiameter = 30;
angles = new Angles(0, 180);
circleColor = new Color(255, 125, 0);
semiColor = new Color(125, 125, 125);
// Using these, variables to create the body.
circle = new ColouredCircle(circleDiameter, imageLocation, circleOffset,
circleColor);
semi = new ColouredSemiCircle(semiDiameter, imageLocation, semiOffset,
angles, semiColor);
}

// Part of the applet not used in Part0.
public void start() {
}

// Part of the applet not used in Part0.
public void stop() {
}

// Part of the applet not used in Part0.
public void destroy() {
}

/**
* Display the shapes created in this Applet.
*/
public void paint (Graphics g) {
semi.paint(g);
circle.paint(g);
}
}

Any help at all will be very much appreciated!
Ashley