All I want to do is go to a lead and add a call back time and reminder i.e. "Today at 13:45". And at 13:40 (for example) it pops up a reminder. If the prospect is not in I can just make a note and duplicate the entry changing the time to say "15:30".

 When I go to the lead and add 'new task' it only gave me a date i.e. not a time. Zoho customer service phoned me on another matter  and when I asked the question they said I had to switch to the 15 day trial to see this. This I have done but there is no option for time. 

Could you please let me know how to do it.?

Many thanks,

Dom