1、Look at these two angles. fold up one of it inside, and the other outside. Then open it. Do you know how to open it? Let me show it to you. Take here and open it. Fold up with a standard of edge, and tidy up the lines. So does the other side. The second step is finished. Let's follow the third step.
2、The third step is starting. It is very important. Fold it in half along the straight line. So does the other side. Then open it. Do you see the four angles? Fold it in half which is on the top. So do the four angles. The third step is finished.