It's a bit hard to explain, but basically, there are two different components. First, there is the "body test" component where you get weighed and it checks your balance on the board. This lets you chart your weight/BMI/balance/wii fit age (sort of a bogus number it calculates based on how well you "balance" on the board -- kinda silly) over a long period of time -- really cool if you are trying to lose some weight as I am.
Then the second component (the more important one) is a collection of games and exercises that get you moving and stretching.
1. There are Yoga exercises to select from (fairly traditional Yoga poses -- it demonstrates them for you if you don't know how to do them, and also rates how well you do the pose based on how you're putting your weight on the board).
2. Strength training: these range from push-ups to leg lifts and all sorts of exercises I've never heard of. It works just like the yoga-- you can get a demonstration, and then you do the exercise with your "trainer" (you can choose a male or female) and it rates how well you do it.
3. Aerobics: these are really great for getting exercise -- they are mostly "games" that get you moving around. There is a hula hoop game that can be quite a workout, there is "rhythm boxing" that is sort of a cross between boxing (you punch with the wiimote) and a DDR dance-type game. There is a step game that is like a DDR dance game, but you are stepping and kicking in time to the music. There is a running "game" that I NEVER play because it's not really a game at all -- you put the wiimote in your pocket and "run" in place through a course. A lot of people like it, though -- I think it's just me who hates it

. There might be a couple more.
4. Balance games: these are a mixed bag. Basically, you are improving your "balance" (how well you distribute your weight on the board) by playing minigames like skiing, tightrope walking, etc. I don't really play them because I think the idea that we need to improve our "balance" to be physically fit is nonsense. But they are fairly entertaining.
There aren't really "routines" -- mostly, you just pick and choose among the games and exercises -- you can do them in whatever order or in whatever amount you like. I find that it really helps me get moving and get exercise (and this is from a died in the wool exercise hater) without it being a totally boring chore. Some of the games or exercises are more or less good at getting you to work up a sweat, though. It's hard to get a sustained, demanding workout. But for lazy folks like me, it is great.
