Prepare boba per package instructions. The instructions on my package were to bring 5 cups of water to a boil. Then add boba and cook until "plumped." Then cover, reduce heat to medium, and simmer for another 5 minutes.
To make the smoothies
Place the mangoes, ice, and condensed milk in a blender. Blend on high until ingredients are completely pureed.
Add about 1/4 cup of cooked boba into a tall glass. Pour mango smoothie puree over the boba.