Hi joanscraftworld,
under Appearance => Menus in your WordPress dashboard you can create custom menus and add menu items as you like. Here you can find more information: WordPress Menu User Guide.
I am familiar with the menu maintenance functions and that is a nice guide, however, when I’m updating my menu I do not see where I can select PRODUCT CATEGORIES to add to my menu?
You could for example add the links to your “Product Categories” as custom links to your menu. You should see an option to add custom links as menu items when editing your custom menu.
On your menu page in the WP Admin, in the upper right corner you’ll see “Screen Options”
Click that and then check “Product Categories”
