First, the beef bones should be soaked in water for 12 hour, and the water should be changed two or three times in the middle.

Bone soup must be cooked with fire before it can be boiled white.

You can't put the bones in until the water is boiled, and you can't add too much water. Too much water makes it difficult to boil the soup white. When the soup becomes thick and white, like milk, just add a proper amount of boiling water and boil it.