The TALL stack, a combination of Tailwind CSS, Alpine.js, Laravel, and Laravel Livewire, is used to build the phone tree application. The application features a user-friendly dashboard for customer agents to communicate with callers effectively. A Twilio Programmable Voice API is integrated into the application to handle call routing and processing. Ngrok is used to expose the application to the internet, making it accessible via a public URL. The application includes methods for different call scenarios, such as handling caller input, connecting with agents, and making calls to agents from the queue. A simple dashboard allows agents to accept incoming calls from Twilio's Programmable Voice API.