There is a comment box at the bottom of that page!
There is only one dynamic home or front "page" per blog, where your posts are automatically added in reverse chronological order. On each post, you can allow comments from readers.
You are trying to use a page to make "posts" but each "post" is only a paragraph on that page. The comment box appears only on the bottom of that page.
The key is to understand the difference between posts and pages, then to learn how to use categories and custom menus to organize your site.
http://en.support.wordpress.com/post-vs-page/
http://en.support.wordpress.com/pages/
Post to Pages
It’s not possible to add posts to pages. However, you can use categories to create a similar effect.
http://en.support.wordpress.com/posts/
Here is an interesting article about posting to a page:
http://wpbtips.wordpress.com/2010/06/30/posts-on-pages/
and an article about custom menus:
http://wpbtips.wordpress.com/2011/12/19/custom-menus/