Organizing your posts is as easy as choosing its category.

I would like this post to fall under the category of ‘classes.’

If you look at the top menu, you can see it is one of my links. It is not, however,  a page. It is merely a category. This post will show up under that category because I have chosen Classes under the category menu (sidebar).

It is important to understand that the content of your site primarily consists of pages and posts. How you organize (or aggregate) that content falls in the areas of categories, tags, and menus.  This is how a Content Management System (CMS) works.