Hey,
ok, so from the first look the namespace of your action should match the folder path so it should be "App\Action\Empacota"
If you create a class in the src/ folder you can then simply use this class directly as action by clicking on the right edit button
at the action dropdown, there you can then enter the complete class name "App\Action\Empacota\LoadProducts".
If you use the PhpProcessor you can simply write a simple PHP file without a class which contains the action code.
Regarding the file_get_contents API call in your class, you could also create a HTTP connection where you configure the base url and then you can