Replace
$DB_ADDRESS="";
$DB_USER="";
$DB_PASS="";
$DB_NAME="";
with
//DATABSE DETAILS//
$db_host = "localhost";
$db_name = "put_user_here";
$db_pswd = "put_password_here";
$db_login = "put_name_here";
mysqli_set_charset($conn, "utf8");
//SETTINGS//
//This code is something you set in the APP so random people cant use it.
$SQLKEY="secret";
This is how I manage to connect in 000webhost