Countdown to wedding clock?

Hi,
I was married in July and was given that little countdown to your wedding clock as a gift...I think you all know what I'm talking about...it says Time Remaining and Our Wedding Day on it...well I threw away the instructions, but want to give it to my friend who was recently engaged, but I don't remember how to program it...I think I got the clock with today's date and time programmed, now I just have to program her wedding date...and it's so confusing, can anyone who has this help me???
TIA