Place the trivet into the bottle of the instant pot. Pour in liquid (apple juice or water, apple cider vinegar, and liquid smoke if using.)
Place pork rib onto the trivet standing up in a coiled position (with the thicker side towards the bottom.)
Close the lid, turn pressure nob to sealing position.
Set to high pressure with cook time of 25 minutes. After that, natural-release for 15 minutes. If there's any pressure left after that (the pin hasn't dropped) then quick-release the remaining pressure.
Remove ribs with 2 sets of tongs onto foil-lined cookie sheet, laying flat.