Place the steam rack inside the Instant Pot. Fill the inner pot with 2 cups of water. Stack corn on the steam rack. Close the lid and turn the steam release handle to the SEALING Position. Select STEAM and adjust the time to 12 minutes of cooking time. Steam corn. When it is done, wait another 5 minutes before venting. Using a large spoon turn the steam release handle to the VENTING Position. Once it is done venting, open the lid and take out the steamed corn and enjoy.