This explains the differences between posts > http://en.support.wordpress.com/post-vs-page/
Pages http://en.support.wordpress.com/pages/ that we bloggers create are static ie. they do not automatically update with new content. Only dynamic pages (ie. categories, tags, archives) which are automatically created by the software when we publish a post will update automatically.
There is only one dynamic page for posts that automatically updates in a blog and all posts will display on that page. There is no way to exclude posts from the main posts (blog) page. By default the front page of the blog will display your posts (not pages) in reverse chronological order, with the most recently published post on top. If you do not want all the posts to show on the front page, then you can create a static front page http://en.support.wordpress.com/pages/front-page/
Though there is only one dynamic page in a blog for posts and we cannot post to more than that one page, we can create the appearance that we have posted to more than one page. We organize posts by assigning Categories to them. You can create a custom menu and add the dynamic categories pages created by the software into the custom menu. Note that until there is one published post in any category there is nothing that can be displayed on the dynamic categories pages
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/