The DEMO version only includes 4 pages:
http://sg-mietenkam.com
http://sg-mietenkam.com/joomla/index.html
http://sg-mietenkam.com/joomla/impressum-der-sg-mietenkam-ev.html
http://sg-mietenkam.com/joomla/kontakt-mit-sg-mietenkam-ev.html

It is possible to download these free files and install them on your server, so you can test how the site works.
Visit https://www.waybackmachinedownloader.com to buy a fully functioning site.
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