How to set up MediaWiki after installation?

Question

MediaWiki

Essence of the question: after a successful installation, I can not log in, although I specified the data for authorization.
As far as I understand, it is necessary to add some kind of extension for the engine and register it in LocalSettings.php
But I can't find the normal instructions for installing it.
OpenBSD-6.8 php-fpm 7.4 mariadb-10.5.5v1 nginx-1.18.0p0
mediawiki-1.37.1
also tried
mediawiki-1.35.2
With the same result.
It was necessary to update a long time ago, but I kept pulling - and now ... No way. In principle, it is necessary to deploy php-8 already on 7.0