Okay at this point I would recommend you to download the appliance again. Something went wrong.
You should download it from here: https://www.univention.com/products/univention-app-center/app-catalog/owncloud/
Thank you I downloaded again and looks like storage connected. How should I proceed further if I want another persons share files in this storage?
If you don't enter the users this storage should be available to - all users on your owncloud have access to it.