How does is Android, PHP, SQL, JSON, and Remote Databases work together?

http://www.mybringback.com/tutorial-series/12924/android-tutorial-using-remote-databases-php-and-mysql-part-1/

As I ' ve mentioned, our Android apps and a remote MySQL database can ' t communicate with all other directly without it being An incredibly tedious process. It would is like a Chinese person trying to talk to someone from Iceland. We don ' t want to play charades if we don't have the to, so instead, we'll get an interpreter. This interpreter would be PHP. PHP would do any of the talking for us. For example, if we want to create a new user for our application from our Android device, we'll want our application to There are some input fields, such as username, password, favorite kind of cheese, etc. When the user fills out this information and hits submit, we'll pass the information to our PHP Web service. The Web service would connect to the MySQL Database, and find the "Users" table and insert a new row into the MySQL Databas E with the information is sent from our Android device. Once US row is created, we'll have our WebService display some JSON data and would tell we whether we entered The data successfully or not. Lastly, our Android device would parse this JSON data and display a "Success" message, or a "Failure, please try again" mes Sage.

The process in visual form would look like this:

How does is Android, PHP, SQL, JSON, and Remote Databases work together?