Hi Mirella
CiviCRM works with Joomla 1.5.x .
I’ve got it installed on my site for testing purposes. The extension is a very detailed extension and also is very time consuming when it comes to configure it the first time around.
You certainly will need the documentation when it comes to configuring it.
According to CiviCRM’s site, any part of the component which is not available in the install will refer to Drupal’s administer instructions.
E.g. The access control is not available in the joomla installation hence the manual only refers to drupal.
From my experience majority of the component’s features are available in Joomla.