If you have not exceeded your alotment of containers you have the ability to create a new one.  Go to the "My Containers" link and click on "Create Container".  This container will contain its own database, instance of Zend Server and applications.  You can choose between PHP 5.3 and 5.4 and you can choose between using the Zend Debugger or Xdebug.  Additionally, if you have need to send email you will need to set up a server.  For a vast majority of circumstances you will not need to send out email to third party web servers and so you only need to set up the host as the MX record for your domain if you want to receive test emails