Soak orange or tangerine in salt water for 15 minutes. For 1 cup of water, 1 tea spoon of salt is enough. (This step is optional. It is in some recipes, but most of the recipe skip this step. I think the idea is to clean the orange or tangerine better.)
Cut the top of the orange or tangerine as how it is in the picture above, and add about 1/2 to 1 tea spoon or salt to the opening area. To have better result, some people recommend using fork or chopsticks to poke salts into the orange/tangerine.
Place the top of the orange or tangerine back to close the opening. Then put the orange in a bowl without water. Then place this in a steamer for 15 minutes.