Parent drop in menu

Hi, On Catch Everest Pro you have something that you call "Parent drop" (http://catchthemes.com/demo/catch-everest/) - I just updated my Theme and would like to know how I Create a Parent drop. If you look at my site http://www.andersin.eu/om-andersin-ad-finem/ If you click at "Om oss" a page displays. What I would like to do is to have "Om oss" in the menu and when you click on it the pages below are the only ones that I can choose from. Regards, Eva