I'm not sure I understand the question to be honest. If what you want is sub-menu items to appear in your main menu then this should happen automatically for you. If you're using the Playtime or Darktones themes then the items will be hidden until you select the top menu item. (i.e., if you have several pages inside News these will be hidden from the nav until you click on News)

There are currently no themes with pop-down menus that show sub-items when you hover over them, or anything like that. Though we'll be looking to provide that sort of thing in some new themes currently in development.

Thanks

Joe - Voice Admin