Please read http://manual.cakephp.org/chapter/installing. 

It is generally necessary to create a postgres or mysql database and then:

cp \
/var/www/vhost.foobar.com/htdocs/app/config/database.php.default \
/var/www/vhost.foobar.com/htdocs/app/config/database.php

Followed by editing the connection settings:

vim /var/www/vhost.foobar.com/htdocs/app/config/database.php

You may also need to modify your apache configuration or vhost file to allow
overides and do rewrites.