To make cold and icy broth, slightly freeze the broth packets. (It takes about 3 to 4 hours.) If the packet was kept in the freezer, defrost it in the fridge for a few hours.
Boil the noodles in rolling boiling water for 2 to 3 mins. (Follow the instructions from the packet.) Drain the water and rinse the noodles in cold running water a few times.
Place the noodles in a bowl (you can even use a chilled bowl for extra coldness) then add the broth. Optionally, garnish with a boiled egg, cucumber, pickled radish and sesame seeds.