To manage mySQL databases, you can access the online tool 'phpMyAdmin' at http://mysqladmin.yourdomain.com (replace yourdomain.com with your actual domain)
Enter your Database username and password, and you'll find a list of all databases assigned to you.
If your domain is not active or has not yet propagated, then you can use http://mysqladmin.servername.com/
NOTE: servername.com is the domain name assigned to the server on which you are located. It is mentioned in your welcome email, you should replace servername.com with the actual domain name of the server mentioned in your welcome email).