call reminder

call reminder

Hi,
Just trying to get my head around Zoho and have looked this up in the forums first.
How do I set a call reminder for say "10am on 28th January"?
It is not a recurring event and if they are not in I just want to set it for say.. "1pm on the same day" and for the system know I had previously tried at 10 i.e. it has logged it automatically.

Many thanks,
Dom