Hi, you can try mongo official tutorial from here: https://www.mongodb.com/languages/mern-stack-tutorial But i think there are some grey points in this tutorial and also recently they fix some errors cause some funtionalities dont work. Also they used old class component rather than function component which is most popular right now. So my offer is :) you can try my repo: https://github.com/brkkartaloglu/mernexample
Don't know if you've found a good tutorial yet but here's a straightforward one: https://www.freecodecamp.org/news/how-to-deploy-a-react-app-with-an-express-server-on-heroku-32244fe5a250/