Hi manolo2001,
if you decided to install ownCloud as an ClearOS app I’d recommend to ask this question in a ClearOS forum (what you obviously already did), since they are bundling the apps. I am afraid we cannot help you with this.
Then, the ClearOS app i found at https://www.clearos.com/clearfoundation/software/clearos-7-community/marketplace/server/ownCloud_for_Business looks highly outdated. You should not use this, if this is the only option.
Additionally I do not see why they want to charge you when ownCloud itself is free (unless you choose to buy some extra support or nedd some enterprise apps).
From my point of view I’d rather not fiddle with this variant, I’d perform a manual installation.
Manual installation is documented at https://doc.owncloud.org/server/10.7/admin_manual/installation/manual_installation/manual_installation.html
From what I read on Wikipedia, ClearOS is based on RHEL (Red Hat Enterprise Linux), so I guess you can search for additional documents discussing ownCloud/RHEL installations.
Finally, ClearOS does not convince me at all. Consider changing your distribution, if this is an option for you.