Here is a Gr8 video showing the process of making sushi rice.
First, place the rice in a large bowl and fill with cold running water, letting the water hit your hand to disperse as it goes onto the rice. Gentle is the key word. You don't want the water to break any of the grains.
Swish your hand through the water and the grains then carefully drain the water off the rice and repeat this process until the water is clear. Be sure you are using cold water.
Drain one last time and gently refill with cold water. Let the rice soak for at least 20 minutes. All the grains will become a lovely bright opaque white.
While the rice is soaking, place the vinegar, sugar and salt in a small saucepan and gently heat over medium heat until the sugar and salt is absorbed. Remove from heat and let it cool to room temperature.
When the rice is finished soaking, drain one last time and place the rice into a heavy saucepan with a lid. (I use my enameled cast iron pot.)
Fill the saucepan with about 2 ⅓ cups cold water, again gently. Place your hand flat on top of the rice, the water should come over the rice to the top of your pointer finger knuckle.
Place the pan over high heat and bring to a boil. Cover, turn the heat down to low and simmer for 15 minutes.
Then remove from heat and let stand covered for another 15 minutes.
When 15 minutes is up, loosen the rice from the sides of the pan and gently dump into a flat pan, I used a 9" x 13" glass casserole. If any of the rice sticks to the bottom of the pan, leave it there. Those stuck grains will compromise the texture of the rest of the rice if you force them from the pan.
Pour half of the vinegar mixture over a spoon onto the rice and gently turn the rice to mix. Then repeat with the rest of the mixture. Continue gently turning the rice mixture over and over until well mixed.
Let cool at room temperature. Your rice is now ready to make your sushi!