I am trying to put all the peaces together I found about autoloading a class in composer but I can't make it work. Every example I see is missing some part. Basically it comes down to two files with 4 lines:
index.php
$loader = require 'vendor/autoload.php';
$loader->add('Vendor\\', __DIR__.'/../app/');
new Vendor_Package_Obj();
app/Vendor/Package/Obj.php
class Obj {}
I also tried psr-4 and all thinkable combinations of folders and names for `Vendor Package Obj? but no luck finding a working solution.
How can I autoload a file with composer using any of those standards?