If you are new to step then I would suggest a non-Cathe workout that teaches you the basics first. I started by using Kathy Smith's Step Workout. Otherwise I found it was very confusing to try to learn the steps with the more complicated tapes like Cathe's.
I don't have the Wedding tape but the general consensus is that this is the best place to start with Cathe.
With regards to a step, get the full length original health club step - you will really appreciate the full length when you get more into step videos.
Hope this helps,
Lisa