Creating Hierarchical Categories
If you have a large number of categories that can be grouped together, it makes sense to organize them into a hierarchy.
To create hierarchical categories
Navigate to the Tree View of the Category Tab.
Highlight the category that you would like to assign a parent node.
Select a parent from the drop down list of Parent Categories, and then Save to commit the change.
Repeat Step 2 and Step 3 for all categories for which you would like to assign parents.