How do you create an auto responder when some one emails the help desk & & ticket is created?

How do you create an auto responder when some one emails the help desk & & ticket is created?

Hi,

Evaluating the software & cant seem to work out how to send an auto responder to advise what the ticket number is.

I can see how to do it when ticket is assigned but I don't want to do that.

Thanks in advance

Todd