How to deploy React/Node app to Heroku with server and client folder structure?

so Ive finished my first app and I want to deploy it to Heroku, but I keep getting error No default language could be detected for this app. Ive read that you need to have package.json in your root directory. My directory looks like this

AppFolder

client -> package.json + /public + /build folder + /src -> all react components
server -> package.json + app.js(main file) + .env + db.js (database pool) + /routes folder

Is there a way how to keep this file structure and still deploy it succesfully?
Should I commit /build folder to github as well? (Its in .gitignore originally) and its created in /client folder, however in some guide I was trying to follow they moved it to /server folder. Id like to use continious deployment as I still need to test responsivnes + finish some details.
Also Im using MySQL, will I be able to host my database on Heroku as well?

Solution

All right Ive figured out how to overcome this issue with folder structure. On Heroku go to Resources -> Add Buildpack -> And you want to add a gitpack from github named subdir-heroku-buildpack, author is timanovsky HERE. Ive came around this information in this video: VIDEO.

Or there is a way using git subtree, but for beginners as I am I find the first method more easier.

Also for the front-end part and MySQL Database, both that I successfully deployed using Heroku (Database) and Netlify (React app) Ive used this video: VIDEO2. It shows how to upload your back-end to Heroku as well, but with the traditional heroku-way folder structure.