drop down menu option

hi
i am using the ‘blue wedding theme’ as standard and would like to have the navigation as a drop down menu. in some themes i have looked at you simple select a page as the parent and the new pages appear under that but this doesnt seem to work on this theme . any ideas or is there a plugin that will fix it for me ??
http://www.jackie-anne-bridal.co.uk is the start of the site and in the example of the ”useful links’ i would like to have the drop down show things like car hire honeymoon, venues etc

Hope someone can help
regards

peter E