Billing Class - Properly Overloading Operators

I was told to create a class named Billing that includes three overloaded computeBill methods for a photobook store.

The first method takes the price of the book ordered, adds 8% tax and returns the total due.
The second method takes the price of the book, and the quantity, adds tax and returns the total.
The final method takes the price, quantity and a coupon discount, adds tax and returns the total.

All of this I have managed fairly well, although I keep getting a strange error at the end of my program that the constructor is undefined. The problem bits of code(the one throwing the errors) are under the comment //Enter values into each of the methods

Code:

package org.CIS406.lab2;

public class Billing {
//Declarations
double bookPrice;
int quantityOrdered;
double couponValue;

[Code] ....

My first thought was to create a constructor for each of the methods that I am using...