Measure out the amount of rice you'd like to cook. The 180ml measuring cup that came with your Instant Pot is best, but you can use other cups. Just remember to stick with a 1:1 ratio of rice to water. Use the same cup to measure water that you did for rice.
Add your rinsed rice to the pot. A special rice strainer like this one sometimes comes in handy. It also guards against losing grains. As the old wives' tales go, losing just a few grains is big time bad luck.