How to diagnose a connection error class?

Put aura router via composer. Connect:

include_once 'vendor/autoload.php';
use Aura\Router\RouterFactory;

Error Fatal error: Class 'Aura\Router\RouterFactory' not found in...
Here my knowledge ends, he's looking for according to the PSR file? RouterFactory.php? It generally is not in any folder. The folder structure of the files within this aura

How to understand that he needs to connect?