I finally manged to get Clean URLs to work on my test Drupal site. First I had to enable mod-rewrite for Apache (a2enmod rewrite, advice from http://www.epicarena.com/c/Linux). Then check that php was installed - yes, it came with Drupal. Took me a while to work out how to get the test page to work though. Then had to change Apache2.conf to AllowOverrideAll and AccessFilename .htaccess. Finally enabled RewriteBase/Drupal in .htaccess, and it worked. The page I mainly used was http://drupal.org/node/15365.

I've also found out that I can conveniently edit files as root by doing sudo gedit to open gedit. I'm not much good with terminal. The manual is proving very handy though, I've now managed to find and change permissions on the files directory using the manual (it's slow work!).