Standard Catalog
To create a root category in a standard catalog:
Select the Catalog Management>Product Catalog window.
Click the New Item button in the upper right. The New Item dialog box appears; make sure Category is the selected item type
Fill in the Name field (required) and set the Root field to true.
Fill in any of the optional fields you want and click OK.
The new category appears as a top-level category in the catalog tree.
Custom Catalog
To create a root category in a custom catalog:
Select the Catalog Management>Catalogs window.
Select the folder in which the catalog to which you want to add a category exists.
Double-click the catalog to which you want to add a category, so the catalog name moves to the left-hand panel.
Select the catalog, so the name appears highlighted.
To create a new category, click the New Category button. To add an existing category to the current catalog as root, click Add Category.
Fill in the Name field (required) and any optional fields, then click OK.
The new category is automatically added to the rootCategories
property of the catalog.