Second step is to run these commands from the command line:

mkdir -p ./extensions/SemanticMediaWiki
chmod ugo+rw ./extensions/SemanticMediaWiki
composer require mediawiki/semantic-media-wiki "3.0.0" --update-no-dev
composer require mediawiki/semantic-result-formats "3.0.0"
composer update --no-dev

Third step is to add

enableSemantics( 'example.org' );

to your LocalSettings.php and change that “example.org” to your URL. Then just run this:

php71.cli maintenance/update.php

to finish.

That’s it. 🙂