Thhere is only one dynamic (continuously updating) page in a blog for posts and we cannot post to more than that one page, but we can create the appearance that we have posted to more than one page. We organize posts by assigning categories to them.
It's critical for you to understand that it's not the static pages that we bloggers create that will update. Static pages cannot and will not automatically update. Delete the static pages you created. Then create a custom menu and add the dynamic (continuously updating) Categories pages to it. http://en.support.wordpress.com/menus/
Here’s a link to a custom menu walkthrough > http://onecoolsitebloggingtips.com/2011/08/11/wordpress-com-custom-menu-walk-through/
There are many common errors, misunderstanding and misconceptions when creating custom menus and you can read about them here > http://wpbtips.wordpress.com/2011/12/19/custom-menus/