open the 'upload/includes/' folder. In this you will find
config.php.new. You should rename this to
config.php and then open it in a text editor. The config.php file is commented throughout, so you should be able to work out what values to enter for the variables yourself. When you have finished, save the file and then upload the entire contents of the 'upload/' folder to your web server.
When this is done, point your browser at
http://[color=red]www.example.com/forums/[/color]
install/install.php (where
www.example.com/forums/ is the URL of your vBulletin) and proceed to click the Next Step buttons until the script asks to fill in some addresses and names for your board.