In that case I would preorder CAthes new workouts, the first two. They will give you a good base to learn on I'm sure, and then as you feel ready you can order Maximum Intensity Strength, Pure Strength, IMAX 2, the list goes on, obviously.
I think that when I first started Cathe I thought I was in pretty good shape, I was doing Karen Voigts Energy Sprint all the way through and was doing some Firms workouts that were boring to me, but they got the job done, or so I thought. They are good for Beginner/Intermediate I think though. But if I had the option now to do it all over again I would have ordered Cathes new dvd's and skipped the Firm. But that is just my opinion. I found the Firm boring, not everyone feels that way.
I hope that I have helped at least a little. If you would like you could order MIS. Just use much lighter weights than what Cathe uses. She gives great pointers in this workout and it's great workout on it's own and you can grow with it. For Step and cardio, you could start with Kick Punch and Crunch, but I think being that you are a beginner that you should wait for the new workouts for Step anyway. If you get Kick Punch and crunch, get the dvd, you can make up your own workout and do only the light sections and you can grown with it, plus it comes with Legs and Glutes. Once again, you can do what you would like and then grow from there. Either way, get dvd's, you won't regret it at all!
Ok, so that is all the advice that I can give you. Maybe some of our other people on this forum will jump in and tell you more. But for sure, get the new workouts, and then if you would like go with MIS/BM/PH dvd and KPC/L&G dvd. Both of those would be ok for a beginner/intermediate. Just use very light weights and adjust the workout to what you can do. If you are going to try those dvd's. You will see great results though from those two, that I can almost guarantee.
Kathy