A Sandbox is a term related to the sandbox you might have played in and built sand castles in as a child. It is a playground for working on concepts and exploring your imagination. A WordPress Sandbox is basically a copy of a generated page on a WordPress site that is saved to your hard drive for you to play with as you develop your final theme and look for your site. WordPress uses different template files to generate different views on your site. In general, there is the front page view, the single post view, and the multi-post view, used for categories, archives, and search. For more information on the structure of WordPress Themes, see Site Architecture 1.5. As different page views use different CSS styles, at the least you need to put three page views in your sandbox following these instructions.