Using Drupal comes with source code intended to be used throughout the lessons to make following the lessons much easier. In this lesson we're going to take a look at what that source code provides for us, where we can get a copy of, and how to use it. We'll go through the installation process, as well as see how we can switch between chapters in the source code without destroying work you've done on previous chapters. It is important to note that using the source code is very important if you want the lessons to match what is in the lessons. Drupal modules can change a lot over time, and the source code is designed to exactly match what is covered in the lessons. Once you've learned the basics of a chapter by working through the source code, you can upgrade your modules and explore the differences in newer versions, with the base understanding you've gained from the lesson.
Warning: Since this Drupal code is several years old, you must use PHP 5.3. PHP 5.4 or higher will not work. You will need to make sure your server is using PHP 5.3 in order to use this code properly. Many all-in-one servers, like WAMP, MAMP, and XAMPP provide older versions of PHP and a way to switch back and forth between versions.