How can I get a drop down menu?

[melodie11]

Hi,

I have a child theme for Debut on my website, and I'd like to have a drop-down menu. I have tried a pair of plugins but it does not drop down, instead it places menus one above the other. What do I need to do to get it to do the dropdown please? Here is the theme, on a test sub-site: http://test.citrotux.org - the last plugin I tried is https://nestedpages.com/ (still active right now).

Thanks.