The install script configures the LAMP stack for drupal, installs APC, drush, drush make and sets up a database for our drupal. After this we launch the make file which downloads all needed code for our drupal. Now the script will configure the drupal file system, set up the permissions and copy the drupal install profile and resources.
(Wouldn't have linked, except they also linked to Drubuntu and others so they clearly did their research.)