How is this done?
For 3 cups of (uncooked) rice, use ½ cup of rice vinegar, 2 tablespoons of sugar and 2 teaspoons of salt.
Mix together in small pot, on medium heat until all solids are mixed in.
Pour mixture on rice and stir well.
Let rice cool down for a few minutes until it is within the room temperature. Don't put the rice in the fridge to make it cool faster - that will damage the rice. You can however use a fan, A/C or put it by the window.