git clone [email protected]:gitonomy/browser.git /path/to/install
cd /path/to/install
cp config_dist.php config.php

Edit config.php and modify array to return instances of Repository objects on each of your projects:

<?php return array(
    'symfony' => new Gitonomy\Git\Repository('/var/www/symfony'),
    'silex' => new Gitonomy\Git\Repository('/var/www/silex'),
    'twig' => new Gitonomy\Git\Repository('/var/www/twig'),
);

You can also map to bare repositories.

When you have filled the file, launch composer to fetch dependencies and make project workable:

php composer.phar install