Having trouble understanding the general flow of wordpress

I cannot seem to get my head around the flow of wordpress and achieve a few things I want to achieve. Is there a link that explains the relation of pages to posts to categories…? I understand that pages are what essentially make up the site navigation or over all structure. But where I am running into issues is making my home page a static page, yet still be a part of the navigation. Making posts only show up on certain pages (ie About have posts that only show up there and not on the homepage). Is there a link here or a book that you guys can recommend?