The tutorial aims to build upon Miguel Grinberg's previous work in sending scheduled SMS with Go and Twilio by expanding to send scheduled MMS and WhatsApp messages using the same technology stack. The author provides a step-by-step guide on setting up the necessary dependencies, including environment variables for authentication, creating a new Go project, and adding required dependencies such as godotenv and Twilio's Go Helper Library. The code is then written to add the ability to send scheduled MMS messages with a validity period of three minutes, set to be sent seventeen minutes after the code is run. The author also refactors the code to send scheduled WhatsApp messages by activating the WhatsApp Sandbox and updating the SetFrom() and SetTo() calls. Finally, the tutorial concludes with testing the code, navigating to Explore Products > Messaging > Overview to verify that the message was successfully scheduled, and receiving the MMS or WhatsApp message.