Put water into an ice tray - make some ice.
Soak dried seaweed into water for at least 15 minutes. Cut into small pieces.
Cut green onion into small pieces.
Take out a pot, fill with water, and bring up to boil. Once boiling, put udon noodles in. Boil for 2 minutes. Drain and rinse under cold water. Let it drip off excess water.
Cut broth packet and pour into a serving bowl. Then pour in some cold drinking water (½ cup). Pour in vinegar (1T), sugar (½ T) and mix it all together. Also put in some ice cubes (½ cup).
Place in the udon noodles. Then place seaweed and green onion toppings.