To build an automated SMS survey using Twilio Studio and IBM Watson Tone Analyzer, users need to create a new flow in Twilio Studio, which serves as the entry point for the workflow. The flow starts with a trigger that sends an incoming message from a hotel's existing system via a REST API. The first question is sent to the customer, and if they respond with a blank message, the flow splits based on the response to ask the same question again. To analyze the tone of the user's response, IBM Watson Tone Analyzer is used, which provides two endpoints: general-purpose and customer engagement. A Twilio Function is created to extract the tone from the response, and if the tone indicates a positive or negative sentiment, different messages are sent back to the customer. The flow is tested by sending an HTTP POST request to the REST API URL, and if everything works correctly, users receive different messages depending on their response.