How Much Time Per Week?
One, preferably two classes per week is ample as a beginner and when you start to get to grips with the complexities then definitely two. Look for a club that has beginners courses which normally run for a few weeks, often up to the first grading, from which point a person will move up to an intermediate class, or into the main class which will often be split between more tan one instructor, working on groups of different abilities.