Not sure where to put 'debug' => true

Hi do I have to create config.php file? (and the config folder)
the only one I have is in plainkit-master\kirby\src\Toolkit and documentation says it’s in site/config.
Thanks for any help

The Plainkit doesn’t come with a /config folder nor a config.php file, so you have to create both inside the /site folder. If in doubt, check out the Starterkit.