WordPress lets you write either posts or Pages. If you are just writing a regular blog entry, you write a post. These blog posts automatically appear in reverse chronological order on your blog's home page.  
 
Pages are for content such as "About," "Contact Us," “Legal”, and so on. Pages exist outside of the normal blog chronology, and are often used to present timeless, or “evergreen” information about you or your blog site. Evergreen information is information that doesn’t change from day to day. You can use Pages to organize and manage any content.