When you create a new page, you don’t have to provide a link to it on the rest of your blog, such as in your menu. If no one knows what the page is, they won’t be able to get to it. Then you can provide a link to it from another page.
Your site will display links to all of your pages in the top navigation bar (menu) unless you make a custom menu. With a custom menu you can specify which tabs you want to show and where they will link to.