I wanted to install owncloud.
But i have a problem:

On the programm page stays:

The first time you connect:

  • Create your Admin account, type in a username and password.
  • Click Storage & Database or Advanced to expand the submenu.
  • Database type = MySQL
  • DataFolder = /var/lib/owncloud/data
  • Database User = root
  • Database Password = dietpi
  • Database Name = owncloud
  • Click Finish setup to complete the Owncloud setup

I have created an account and pasword, but after that i can’t see any button with Storage & databace or Advanced to make the other settings.

Can somebody tell me were i can find these settings?

Reinstalled Owncloud, then i was able to do the settings.
But i do have another question.

How can i acces Qwncloud from the internet?
What port do i have to open?
I have tried port 80, but i have another server running on port 80, and i cannot open 2 ports on 80

The default port for Apache on a DietPi install is 80.
owncloud would be accessed (as you know) by http://yourserver/owncloud

in order to access this through your firewall, you can use a router that can redirect to a different port (so your router would take http://your_external_ip:81 and send the traffic to http://your_internal_dietpi_ip:80)

or you can reconfigure Apache to listen on a different port (such as 81 or 8080)…
Here’s the basics, but you may need to Google for more details

You can use rhkean’s suggestion along with noip. Follow the instructions here: http://dietpi.com/phpbb/viewtopic.php?f=8&t=5&start=10#p58
Make sure to enable port forwading on your router and that should be it. Whether its local or online, you will be able to reach your ownlcoud from anywhere.