Step 5: setup own cloud
The easy way to setup the external drive is to use gparted on the Pi
and the from inside the GUI open a ternmail and type
$ sudo gprarted
from here you can partion and format the drive
Once done give the web-server permission
$ sudo chown -R www-data:www-data /media/owncloud
All that needs to be done now is to setup owncloud
in a web browser type in https://IPADDRESS/owncloud
Choose a user name and password by typing then in to the user name and password box
click advanced and changed the data location to the place of your external drive in my case it's /media/owncloud
The click finish and you are done.
You should now be able to upload files. To play video files you'll need to enable the video player app.
To setup external access to your device I would suggest using DyDns or Noip.