From DAViCal Wiki
The creation of new calendar for a user depends on the features supported by your calendar client.
Creating a Calendar in the Client Software
With programs such as iCal, SOHO Organizer and Mulberry, the software provides a UI to create a new calendar. These should work fine, since DAViCal does implement the MKCALENDAR command that these clients use.
In iCal, simply select the home calendar, click the + sign and create a new calendar, which will be stored under the logged-in user in DAViCal. Note that if you are viewing a calendar that you don't own, but that you have a relationship to, the creation of the calendar will fail. You need to be either the owner of the calendar, or have Admin rights to it.
Creating a Calendar in the DAViCal Administration Pages
Since Release 0.9.7.4, new calendars can be directly created via the DAViCal UI. Alternatively, an existing calendar .ics file can be uploaded via the user page of the DAViCal UI.
An empty VCALENDAR (.ics) file looks like this:
BEGIN:VCALENDAR VERSION:2.0 PRODID:-//PYVOBJECT//NONSGML Version 1//EN END:VCALENDAR