如何在prestashop中的父类别中显示子类别？

So as you can in this image, you can hover over the nav button 'Eliquids' and 4 categories will show up in a drop down.

All my products are contained within those four categories, however, if you click on the word 'Eliquids' it's self, it takes you to an empty page being as all the products are stored within their respective category.

On the left you can see the categories being displayed in a side navbar.

How can I make it so all four sub-categories (Chef's Blends, steamgunk etc) show within the category 'Eliquids' ?

Is this possible via the back office as I can't seem to find it my self. Otherwise, is it a case of editing the source code ?

Version: Prestashop 1.6.0.9

Theme: Prestashop default bootstrap theme

You need to configure that a the "Theme configurator" module. There is "Display subcategories" at the bottom at the "Configure" page.