All categories need to go into "Browse". To add a new category to a page you can click the Category button at the bottom of the page and type in the name you'd like your category to be called. — better is the category box in the right column.
A full list of existing categories can be found at Special:Categories.
This category has the following 22 subcategories, out of 22 total.
Pages in category "Browse"
This category contains only the following page.