I installed owncloud 8.02 in Ubuntu server 14.04. Everything is perfect. Except when I tried to change Logo, Title, etc. I found the config.php file is missing from the config folder. Only sample config files are available. I tried to change files in core/img core/css folder. nothing works.
I use Filezilla and PuTTy to login and edit files.
Sample config files are a pretty common thing to do, it's to avoid sharing sensitive information like database passwords that might be part of the regular config.
You can simply make a copy of it, removing the "sample" part, and then change it to your needs.