There are a lot of kind brewing style in the world and no one can say one is true but others are false.The important point is the tea to leave its extract into water in any brewing style.
To brew a good tea, you need a good master. A good master can produce a good brew from a low quality tea.
It is accepted to brew tea in 3-5 minutes in general, but this is not a strict rule and the time vary in different type of teas.
It is accepted a porcelain teapot to be best for brewing tea, but other kind of teapots can be used