To create SMS notifications from tweets, retweets, and mentions with JavaScript and Twilio SMS, developers need to have Node.js, Ngrok, Twitter Developer account, and Twilio account. They must first set up a Twitter app by creating an app on the Twitter Developer page, enabling sign-in with Twitter, and setting permissions. Next, they need to generate credentials for their Twitter account and Twilio account. Then, they can create a Node.js project using Express and install required dependencies. The application will use Twilio's SMS API to send notifications. To receive notifications, developers must register a webhook on the Twitter Developer page. Once registered, the webhook will listen for incoming events from the Account Activity API and send corresponding messages as SMS using Twilio.