How to create sub-nav / drop down menus

Hi Kishor, I love this plugin! Thank you for creating it – I am working with a theme that only has one available menu location and I needed more. This plugin did exactly that and very easily!

However, when I add sub-pages to the newly created menu, they do not show up as a drop down or sub-navigation menu, they just display in line with the rest of the menu items. I realize I probably need some more php in the Theme Header file to accommodate for this – but just wanted to check if I might be missing something in the plugin itself? A setting or something I could do to achieve this without having to write additional PHP?

Thanks for your help!