Hi @herman08, have you install apache package ? if yes, this file must be placed in /etc/apache2/sites-available/
after done these lines :
sudo a2ensite nextcloud.conf
sudo a2enmod rewrite
sudo a2enmod headers
sudo a2enmod env
sudo a2enmod dir
sudo a2enmod mime
sudo systemctl restart apache2
for a full install check this post : Making a nextcloud server on old laptop with personal domain - #5 by Mageunic