What is the best approach in creating a chatbot from a beginner’s perspective?

Good day everyone!

I’m a college student working on a medical chatbot. It will only feature some simple functions like diagnosing common illnesses (cold, fever, flu, etc.), answer health queries, and book appointments.

My college professor recommended that I should use Dialogflow for the chatbots NLP. I’ve already had a framework approach in mind, but my problem is that I have no idea where to start in creating a chatbot.

Furthermore, I’m using MySQL for its database and Heroku for hosting it. I was supposed to use MongoDB for its database, but as this project is in a collaboration with a classmate of mine, I needed to use MySQL as Laravel does not natively support MongoDB.

I hope you guys can lend me some of your knowledge. Thanks!