Anatomy of a WordPress theme

Before getting stuck into the build process, it's important to know how WordPress themes work. If you've looked at any prebuilt theme, you'll notice that it's all contained in a folder, and there's around 12 core files. Some themes, including the Default WordPress theme, include more files which allow extra customisation, but aren't mandatory additions. Here's an overview of the main files you'll be working with:

• header.php - Contains everything you'd want to appear at the top of your site.
• index.php - The core file that loads your theme, also acts as the homepage (unless you set your blog to display a static page).
• sidebar.php - Contains everything you'd want to appear in a sidebar.
• footer.php - Contains everything you'd want to appear at the bottom of your site.
• archive.php - The template file used when viewing categories, dates, posts by author, etc.
• single.php - The template file that's used when viewing an individual post.
• comments.php - Called at the bottom of the single.php file to enable the comments section.
• page.php - Similar to single.php, but used for WordPress pages.
• search.php - The template file used to display search results.
• 404.php - The template file that displays when a 404 error occurs.
• style.css - All the styling for your theme goes here.
• functions.php - A file that can be used to configure the WordPress core, without editing core files.

Each of these files then contains a series of PHP template tags. These tags tell WordPress where to insert the dynamic content. A good example is the  tag, which pulls in the post title and displays it in your theme:

There's stacks of template tags available, and more often than not there will be one that does exactly what you want - It's just a case of finding it in theWordPress Codex. I've seen many themes that include some complicated PHP coding to achieve a function that's already available as a simple template tag, so remember to browse the WordPress Codex whenever you're stuck!