Accordion to the Documentation I have to place the setup.php into the Grav root and create directories user/sites providing the necessary other directories and files.
But it doesn't work. If I call my setup.php I get following error:
Fatal error: Uncaught Error: Class 'Grav\Common\Filesystem\Folder' not found in */grav/setup.php:14 Stack trace: #0 {main} thrown in **/setup.php on line 14
Maybe someone can help. I think I am missing something completely obvious.