I have edited a nav menu from one of their website templates, but now that I wish to have one of the menus to be a drop down menu I can't get it to drop down. I have created a submenu in the "Nav Bar Properities" page and it shows them in there but when I preview the website it never has it as a drop down menu.

Basically I want one of the buttons on the nav bar not to be a link but when you scroll over it with your mouse I want a drop down menu to appear. How do I set this up? Thanks to anyone who can give me a speedy reply!