React + MySQL

Hi
I have created an app using Code Igniter 4, React and MySQL which is all working locally and allows the user to track their daily nutrition and workouts. My only problem is now I am ready to deploy and not sure how to exactly do this when using React and MySQL with Code Igniter. 
I have put my react app inside the public folder.
Can any recommend any material that shows this being done? Or have any previous experience doing this and can point me in the right direction on where to get started. I was trying to use Heroku initially but I just couldn't seem to get it linked up.
Thank
Jack