Changing the ownCloud welcome page



I am using ownCloud with Raspberry Pi.
I want to know if I can change the ownCloud welcome page. I want to change the html content only and use php of the owncloud as backend. I navigated to the ownCloud directory in /var/www/ownCloud but was not able to figure out which file to change or replace.



the keyword for this is "Theming" where you can find the matching documentation on how to do this here: