I haven't processed any data recently in Deep Sky Stacker (DSS) because I've decided to collect larger amounts of data per night.  I've subsequently, skipped taking dark frames which is beginning to catch up to me.

Here's a link to a web page explaining all the other data which must be acquired before you can stack an image: 

http://starizona.com/acb/ccd/advimcal.aspx

I have to decide how I'm going to collect dark frames.   The easiest way would be to setup the camera on a cloudy night that has temperatures roughly equal to the night of the imaging run.   This can be tricky since cloudy nights tend to have warmer temperatures.