The above link introduces you to the 'loop', which is the basic method that WordPress uses to display posts. Inside the 'loop,' you can use a number of 'template tags' to display the post information that you'd like. The Codex has a list of 'template tags' you can use:
The link in your post places the first post in a special loop, and then makes a second loop for the rest of the posts. If you add a special CSS class to the first loop, you can center it in your stylesheet accordingly.