Use the details that you were sent in your Welcome email when follwing this guide.
CalDAV Setup for iOS
Do the following on your iOS device:
Tap Settings.
Select Mail, Contacts, Calendars.
Tap Add Account.
Select Other.
Under Calendars tap Add CalDAV Account.
For Server enter mail.hostedemail.com.
For User Name enter your email address.
For Password enter your email password.
Enter whatever you like in the Description field. It will be autopopulated with what was entered in the Server field.
Tap Next.
Events in your webmail calendars will now be visible in the calendar app on your device. Any changes made in webmail will show up on your device with a refresh.