To connect your Zimbra calendar to FreeBusy:
- Go to sign up. 
 Or link new calendar if you're already signed in.
- Provide the email address associated with your Zimbra calendar. 
- FreeBusy will try to detect your calendar provider. 
 You can also pick Zimbra manually.
- Provide Zimbra Webmail Address, username and password. 
- Click Sign in. 

