@OrangeRock
I suspect that most tai chi for well-being classes do short form qigong (chi gung) which is a very good place to start if you are a beginner. It's how I started, 🙂
Short form is a series of around 10-16 different moves, you repeat each move as many times as you like then move on to the next move. It is much easier to learn in classes, especially if you might miss the odd week or two.
Long form is a continuous sequence of different movements, maybe as many as 60, although there will be some repeats (such as Cloud Hands). It would be challenging to begin with this style before you have learned the movements in the short form. You also need much more space to do it in!
The thing about tai chi is that it is not just the movements, the breathing that goes with it is incredibly important (you have to breathe in with some parts of the movement and out with others) and this took me at least a year to get the hang of.
You have to grasp the concept of chi (you can feel it if it is well explained!
Balance, weight shifting and foot movements are all important, and you need to set the time aside to focus on it if you are going to get the benefit out of it. All these things are why you need full contact with a proper teacher.
I hope I haven't put you off by making it sound too complicated! 🙂