To send WhatsApp messages using Python, users need to set up their development environment with Python 3.7+, a Twilio account with WhatsApp Sandbox enabled, and the Twilio Python Helper library. They must also define variables for their Twilio credentials, which are stored securely as environment variables. A sample Python script is provided that uses these credentials to send a single message from a test phone number to another test phone number. The script can be run in an activated virtual environment with the necessary dependencies installed. Once set up, users can activate the WhatsApp Sandbox and execute the script to send their first message, which will appear in the recipient's app. Additional tutorials are suggested for further learning on using the Twilio API.