When discussing the best practices of PHP application development, there's one that appears on almost every list: separating the business logic of a Web application from its user interface. This separation lets interface designers work on a site's appearance without disrupting the code of the application developers implementing business-level features and workflows. [...] However, if your project is small enough that you don't need a framework (or if you just don't like them), you can still achieve the same benefits by using a standalone template engine.
He introduces the framework by showing the installation process (via the PEAR installer) and some basic templates with simple replacement string placeholders. He also includes the code to give you an idea of the PHP side of things. With the basics down, he gets into more advanced things like looping, conditionals and including multiple templates inside to make modular templating even easier.