Thank you, got it to work!
I moved the dokuwiki folder's contents to /var/www/html, so that install.php is in that folder.
As an edit to step 7 in the installation wiki, the file
/etc/apache2/sites-enabled/000*.conf
should be edited. The line below goes now as follows:
DocumentRoot /var/www/html
, instead. Restarted the server and it works!
Thanks again for the quick and easy solution!