To add a new category, clik on the "Add A New Category" link.
To create a sub-category, click on the "Category" link next to a category and drag in on top of the parent category.
To place a category above or below another category, click the "Category" link next to a category and drag it in the grey box above or below another category.
To delete a category, click the "Category" link next to a category and then click on the "Delete" link.
To rename a category, single click on the category name.