This should be merged with Calendar Admin.
tiki-admin_calendars.php
You'll see two tabs at the top list and create/edit calendars.
Creating is easy, just put in your values
Name:
Description:
Custom Locations:
Custom Categories:
Custom Languages:
Custom Priorities:
However, at least in 15Feb4 CVS going back and forth between listing and editing you may lose your calendar.
Need to investigate perms on this and figure out who can do what with the calendars.