Log in to your account first. Then go to your control panel ( http://www.zymic.com/zcp/
From there, Login to your website account and go to its control panel (You'll be redirected. This page: http://hosting.zymic.com/user_index.jsp)
Once there, Click the database management link.
There's an option to create user in there.
Once you've created one, You'll have to assign it privileges.
If you have any problems while doing this, Please provide more details.