Trying to use keypad with arduino mega. please help Answered

I have a 4X4 keypad (the same one they use here: http://www.learningaboutelectronics.com/Articles/Arduino-keypad-circuit.php) wired to my arduino mega on ports 14-21. I have a piezo on pwm8. I need a program that plays a diffrent note when each key is pressed, using keypad library here:http://playground.arduino.cc/Code/Keypad. The code on the first link is my base, I just cant get the if statments to work. please help.