Having both a main and sub category

Hi
I've recently had my website created by a design company and they have used ZenCart as the CMS, so far I am really really pleased with it.
The company has added in for me a subcategory and product page, however now that I am expanding I now need to install a 'main' category for some lines of product so that the site is easier to navigate.
Down the left hand side I have a navigation bar which currently contains subcategories, however I would like it now show some main categories within which the subcategories can be displayed.
I just wondered if anyone out there could explain simply how to do this as I'm not exactly an expert.
Any help would be much appreciated! :blush:

Rachael

It would help a lot if you could post a link to your site.

Take a peek at https://www.zen-cart.com/tutorials/index.php?article=55 for info on setting up categories and sub-categories. It's pretty simple.