copy/move config.php.example to config.php.
Update with your settings

$file - File where URLs are stored
$url - URL for your site
$num_last_items - number of previous URLs to display
$rewrite - 0/1 setting to use url rewriting, url will append directly to $url setting.
$history - 0/1 setting to enable displaying previous URLs


Rewriting URLs
If rewrite is enabled and $url is set to http://mysite.com/url then the resulting link will be:
http://mysite.com/url123 where 123 is the link number. The corresponding .htaccess entry would be:
RewriteRule url([a-z0-9]+) /url/?id=$1