Install mysql
Install a web server
Clone ZombieSource repo to the root of your webserver
Create mysql table with this schema /www/db/ddl.sql
Edit /www/application/config.php so that $config['base_url'] is set to the full local path to ZombieSource
e.g. config['base_url'] = 'http://localhost:8888/ZombieSource/www/';
Edit /www/application/database.php with the login credentials for your local mysql installation.
Open a pull request to obtain a code review. Don't commit anything you changed under/config that is only for your local enviorment.