Don't think about it yourself when you meet it. Just look at the animation. It's better to get to know each other emotionally
In addition, the brackets () indicate that these actions are a group and can be completed together very coherently and conveniently. () There is a 2 outside the bracket, which means that the steps in the bracket have been done twice. If you don't understand, you can watch the animation.
Note that the front and back directions of E and D are the same, so E' is clockwise from top to bottom. M and l are in the same direction.
See the figure below for details.