This is raw mochi. It has be cooked before consumption. Add any seasoning you like AFTER cooking it. There are 3 main ways for cooking this.

Microwave
Place the mochi in a heatproof container, add enough water to cover the mochi, and heat for about 2 minutes at 500W.

Toaster ovens
Bake until the surface of the mochi starts to turn brown (4 to 5 minutes).
Let it rest with the door closed for about 1 minute.

Boil (5 pieces of mochi)
When the water boils, lower the heat.
When the mochi rises to the surface, turn off the heat and leave it for 2 to 3 minutes.