infrequent appointment dates

I am using Appt+ to set up a schedule for cast auditions for a show. So I only need to display two days, which will be a few months away at this point. I want to set up 20 slots each on Friday, Dec 14 and Sat, Dec 15. These days will not change. How can I set this up? I do NOT want to display any other days other than the two that we are booking auditions for. Thanks, Alan