I can't access The Flow Welcome screen

When I accessed http://dev.tutorial.local, the following screen is displayed on the screen.

Hey, welcome to the Neos community.

What you see hints at that you don’t have PHP setup on your webserver. Therefore it only shows a listing of the files at the webroot instead of interpreting the index.php file. For example in apache you need to enable the php mod for your PHP version, something like sudo a2enmod php7 && sudo service apache2 reload

In order to give more concrete help, we’d need to have more information on which system you are running on and which web-server setup you chose.

Hope that helped already.