The WordPress Loop is the brains behind your WordPress site. A simple yet sophisticated bit of PHP coding, it generates the content and information displayed on your site, in fact, on each template page on your site. Understanding how the Loop works and how you can customize it to your needs is covered extensively in the article on The Loop in Action.
This is just one of the more than 450 articles on the WordPress Codex, the online manual for WordPress users, available to help you.
By the way, this week we’re moving the Codex to a new and fully redundant hosting situation that will guarantee 100% availability of all documentation regardless of anything happening to wordpress.org.