Question with Conection to EC2 php server

Hello i have a simple app made in unity that i made to understand how to make apps and to learn simple connections to an external database , right now i have a simple database in AWS RDS and a PHP server in EC2 connected to it ,what i need is a tutorial to learn to take simple data like login ,registration and simple questionare answers made in the app and upload them to the database , i understand that is done with wwwform but i cant find good tutorials that explain every step if you guys could help me that would be greatly apreciated