Website Categories

Hi

On my site there are 3 stores and within each store there will be unique product categories:
Because the categories list can be very large, I want to have one page to dispaly the stores and the category lists on one page.
http://www.ontargetsolutions.biz/?page_id=1572

I am trying to understand how to display the category list on this page?

I tried to add a shortcode for the area on the page but I did not see a code that I could use to show the categories. I am sure there is a way to add this, but I am not sure where to locate the correct elements? I also did not see the category in the screen options?