Hi MeToo, thanks for the information, that make things clearer in the discussion.
In my example, the full URL the server is called looks like this
http://localhost/heikokanzler/helloworld.php?param=TestYou can easily check it out by calling the URL from your web-browser and then play around with the param-values or change the script to retrieve different params (see below).
In my example, the script is located under the URL
/heikokanzler/helloworld.php and you pass the parameters to the script in the way
param=value. The script itself looks for the key="param" and retrieves the value (this is often referred as a REST API)
If you want to pass more attributes / parameters to the script, you append them in the way
&another_param=anothervalue&differentparam=waydifferentvalue. Please note that the additional attributes are delimited by a
"&", that differs to the inital
"?" right after the script name.
You can access the params in the script by asking
$_REQUEST['another_param'], i.e.
<?php // save file as helloworld.php
$param = $_REQUEST['param'];
$another_param = $_REQUEST['another_param'];
$differentparam = $_REQUEST['differentparam'];
echo "Hello, World with params=". $param .", ". $another_param .", ". $differentparam;
?>
In Stencyl, change the line
[set <param> to [param=Test&another_param=Test2&differentparam=Test3]]to call the script with the new parameters.
With securing a online game, preventing from hacking and cheating, there's a lot to consider. We do cash games and are faced to this challenge everyday. Not an easy task, but possible

I suggest, you should discuss with your game architect and technical architect / php developer, they should know what to do and advice you as the game developer how to interact with the backend.
Cheers,
Heiko