Answer

Do you want to know enough to take care of your own house or enough to be a professional?

If you want to know enough to become a professional, expect to study intensely for a few years, and don’t expect you can breeze through one or two classes and start charging people. (That’s how the fraudsters got into the business.)

You may have to interview teachers to see whose style you are most comfortable with. Look at the websites of Raymond Lo, Joseph Yu, and Larry Sang.