sub page links not showing

I’m using wp_nav_menu for my main navigation and my sub pages are showing up under it’s parent page or main page link(what ever it’s called). How do I get my sub pages to show up when I hover over its parent page link or main page link?(what ever it’s called)

I tried putting the sub page in the widget and it showed up under the parent page link but I want it to show up only on hover. Here is a link to the example.

Sample

You can see under test it shows the sub page link. I only want it to appear on hover like most themes.