In this chapter, we learned how to create an extension from scratch. Specific to this extension was the usage of an event or observer pattern. We got in touch with the system configuration section by defining our own configuration option. Values assigned to this configuration option were then read via the help of a Helper class that we defined. In Chapter 3, Building the Extension - Logger, we will build a new extension, expanding our knowledge with installation scripts, models, and the other building blocks of an extension.