drop down menu confusion

[wxdqz]

Hi I am still learning and practising with these codes. I am trying to figure out how the cascading menu works. Found one on the javascpript source but I am still having problems. It gives additional pieces to download and add but when I do I still do not get the correct format...what am I doing wrong...Not sure if I am placing in the correct spot..Heeelp mee pleeease!!!! Thanks