This tutorial guides developers in setting up an SMS usage alert system using Python, Flask, and the Twilio API. To start, they need to create a new Flask project, install necessary dependencies, configure their Twilio account credentials, and set up a Flask application with a /usage-alert endpoint that sends an SMS notification when a certain threshold is reached. Next, they need to create a usage trigger in the Twilio Console that invokes this endpoint, which can be done by setting up a low threshold for voice calls. The tutorial concludes with testing the trigger and verifying its functionality.