Automated ordering on WhatsApp is made possible by building a Node.js service using Vonage's WhatsApp sandbox, allowing customers to interact with businesses via messaging. To get started, developers need to create a new directory, install necessary packages, and set up an Express.js server. They also need to add test data, including customer numbers, medications, and prescriptions, as well as configure webhooks for inbound messages. The server listens for incoming messages, checks if the message is related to an order, and responds accordingly. Once tested, the system can be expanded with real data and logic, and eventually applied to a WhatsApp business profile to take ordering live to customers.