http://codex.wordpress.org/Templates_Hierarchy
Though that article might be a bit advanced for what you want to do, it's important to note that Wordpress can have few or many template files that control the content of each section.
The files you will probably want to change, if they exist in your template, are index.php, single.php, page.php, archive.php / archives.php, category.php, author.php, and search.php.
Remember, your theme may not have all of these files, but each controls a particular section of your Wordpress blog and each lists a post or posts with its respective title.