You can create and manage your Categories from from the course list screen.
To Create A Category
1. Click Courses from the top main menu.
2. Click the +add link next to the category section on the left side of the screen.
3. Enter the name of the category and click OK.
4. You should now see your category displayed under the the category section.
5. Click the category to add/remove/view the courses in the category.