Here we configure all the plugin : processing page

Leave the first option selected to have the processing page needed. It's all you need to do.

For special pages like Home, account, shopping cart and other special page (promotion, new poducts, ...) you can select the appropriate option in the list : exemple for account page :

At the end of the list you have access to all categories you create in OS Commerce for exemple you have categories 1 & 2 and subcategories 1 & 2 for each you will obtain this :

That's all you have just finish configuring your new shop system.