Put the corned beef brisket with any seasonings on top of the trivet. Close and lock the lid, turning the steam release valve to closed.
Press Meat and adjust time to 60 minutes. Press Start/Stop.
When cooking cycle has ended, allow for a full 30 minutes of natural pressure release.
After pressure is completely released, open the lid and add the potatoes, carrots and cabbage around the roast. Close and lock the lid again, turning the steam release valve to closed.
Press Steam and adjust the time down to 4 minutes. Press Start/Stop. (The pressure will come back up quickly because the pot and contents are already hot.)
When the cooking cycle is done, do a quick release and lift the whole roast and veggies up out of the pot. Plate together and serve hot!
If you're using a different cooking liquid, feel free to place the meat directly in the pot, rather than up on a trivet. Add cook time if your roast is larger than 2 1/2-3 pounds. Another 15 minutes per pound should be enough.