OMV beginner - cannot apply ownCloud plugin

Hello, i am newbie to OMV and also Linux. I want to create the ownCloud on OMV with streaming possibility (all created and configured first on VirtualBox to learn how to do it, then on other PC which will be a server). Howerver i am stuck on adding ownCloud to my OMV. First thing, the installation process avoids creating partitions (i dont see window with Partition disk choice as it shows in 2:02

). I assume that it causes second problem, i cannot create Share folder in OMV Web interface because none volume exist(found) - 1st attachment shows it.
When i follow this guide ownCloud 7 install on OMV 1 with current plugin I cannot do point 4), cause of reason described above.
Next goes point 9), certainly "...select the self signed cert you just created above from the drop downfor data directory select the shared folder you created for ownCloud, again I used oc". I dont have any certificates installed and cant choose data directory also. I haven't gone further cause previous points doesn't work.
Can you help me, please?

Thank you for reply, i have some other problems which i have mentioned in my second topic (didn't see that this is accepted by Admin already - sorry for that), so this can be continued with my problems:
"I want to install ownCloud on OMV, but have several problems. First, while setup i dont have possibility to choose or create any parition - the window with partitioning just doesn't appear and setup goes on next steps. Therefore in OMV GUI i have to create in manually - firstly doing it on VirtualBox (adding second hrd drive to host machine). I saw on many YouTube videos that peopple also install this on Virtual Machines and they have partition setup, so i dont understand it.Second, when i want to exit (shutdown) the OMV, then after next start ownCloud doesn't work and GUI of OMV shows me "It works!This is the default web page for this server. The web server software is running but no content has been added, yet.". I can access OMV by Webmin, which i also install to have easier access to config files. It doesn't happen on every OMV shutdown, only when i install ownCloud or Webmin and then shut it all down. Also, if i first install ownCloud, then create new partition, and after that i enable ownCloud plugin in GUI - after shut down it crashes and i see "It works..." instead of GUI.Third thing, i don't know how to install Video Streaming plugin to ownCloud. I dont see button to add 3rd party applications.Also, i have some miscellaneous issues with OMV, but first i would like to solve the main ones."

Zitat

If you want to separate your HDD via partitions, you have to install Debian first and OMV on top of it: Howto install OpenMediaVault on Debian 7.x (Wheezy)However, it would be much better if you use a single drive as a system drive and another one for Data. If your system drive fails and you have to replace it, you´ll not loose any data.

As i said in my quote above, i want first install it on VirtualBox, so i dont have to format physical drive every time - when i learn how to setup it properly without crashes, then i want to install it on my other PC.

Now, i managed to install OMV with additional partition and have it in GUI, so its ok with it. I tried to install ownCloud with fastest method, just by applying plugin in GUI, and after doing it ownCloud works. However i turned OMV of by "sudo shutdown -h now", so should have closed safely, but after starting again it has been crashed. I can't access ownCloud and instead of GUI web i have "It works..." error message in browser. I recorded OMV terminal after clean installation and after installing ownCloud and it has changed, so i attach both movies. I hope somebody could recognize what causes this crashes.
Just after OMV installation at VirtualBox:
View My Video
After installing ownCloud plugin:
View My Video

I can upload some logs or any data needed to find problem, just tell me what to do, please.