Hi Diane!
I'm not Cathe and so this might be a little like the blind leading the blind, so let me be sure to add a disclaimer here. I am no expert in this field, but willing to help if I can. If I were you and had 15 pounds to lose, this is what I'd do:
1) Eat clean -- for me lo carb works best -- but you will need to find what works best for you -- read, read, and read about diets, and find your own diet that works -- Eat clean means no processed food and definitely no sugar. You might think of sugar as the bad guy.
2) Get and read the book, READY, SET, GO! by Phil Campbell who will give you all the ends and outs of rotations and such so that you become yourself educated and won't need anyone else to tell you what to do.
3) In the meantime realize that to lose weight and get the most benefits from exercise you must work all three different muscle fibers -- the slow twitch and the two fast twitches, and that there are five important parts of exercise that must be a part of your weekly schedule, (anaerobics, cardio, strength, plyometrics and stretching). Take this at your own pace. If you are a seasoned exerciser and have some good cardio behind you, I would recommend 2 days of anaerobics, 2 days of weight work, 1 all cardio day and 1 day of weights plus cardio. The last day for rest and stretch -- rest is important.
From the tapes you have -- depending on your cardio capacity, you might consider:
Mon: IMAX (anaerobics, plyometrics and cardio --works the fast twitch fibers)
Tues: Power Hour (strength -- works the slow twitch fibers)
Wed: Rhythmic Step (all cardio -- pretty much works the slow twitch fibers and gives one cardio endurance)
Thurs: Muscle Endurance (strength -- works slow twitch & some fast twitch fibers, I believe)
Friday: LowMax (anaerobics, plyometrics and some cardio -- works fast twitch fibers)
Saturday: Bootcamp (anaerobics, plyometrics and strength all in one.)
Sunday: off and stretch
But more than anything, because I am no expert, I would highly recommend that you get and read the book, READY, SET, GO! by Phil Campbell. It made all the difference for me. I went from being confused to knowing somewhat what I should be doing. But do remember that anaerobics must be built up to with cardio endurance. If you have not done that, if you are not a seasoned exerciser, please realize that anaerobics -- especially in hot weather -- can be dangerous, as you are taking your heart rate way up there. The IMAX's cater to the seasoned exerciser -- and if aren't there yet, you can get there by doing Cathe's step tapes until you have good cardio endurance. Then tackle the anaerobics. Just my 2 cents.
Hope this helps.:7
Have some wonderful workouts.