This tutorial aims to create an OpenCart SMS extension that notifies store owners of new orders, customer registrations, and order history modifications using the Twilio SMS API. It requires a PHP development environment with Composer, a Twilio account, and an understanding of OpenCart's MVC framework. The module is created by modifying existing files and adding new ones, including an admin interface to store Twilio credentials, template files for sending SMS notifications, and an installable module that integrates the Twilio SDK. To test the module, the author installed it on their own OpenCart instance and confirmed that it sent SMS notifications correctly. The tutorial also addresses potential issues with SMS region permissions and permission errors. By following this tutorial, users can create a custom OpenCart module that leverages Twilio's programmable SMS API to enhance their store's notification system.