The theme of your site at minimum controls how your site looks and many times may offer a multitude of the functionality. The basics of understanding how WordPress themes work is understanding patterns in the 3-5 core files that are required for a theme. Today's session with walk you through a cursory overview of each of these files so you understand how they all work together to create a WordPress theme. This will be your first step toward learning how to edit or even create themes in the future.
The second half will walk you through the steps of creating a child theme. We'll be focused on child theming one of the default WordPress themes - Twenty Twelve.