The skill of making boutique coffee teaches you how to make milk foam?

As we all know, apart from other factors, the quality of milk foam will affect the quality of a cup of coffee to a great extent. How to make a delicate, shiny, uniform and sufficient amount of milk foam? The whole process is divided into two stages, 1:stretching 2:spinning stage-streching first, to make sure that the utensils, utensils and coffee machines used are clean. Of course