Deleting Calendar posting

An event got duplicated and when I went to delete the new one I get a prompt of "delete all occurances" with a warning that the action can't be undone. Before I hit yes, will this delete the original one (which has the same name)? And if so, how can I delete only the duplicate? If not, then why does the message vague? And I guess my other question is why didn't it jsut prompt ala Outlook - this occurance, all occurances?

And one final - am I missing where there's a help sectin that describes using the calendar?

Many thanks!