Clean 4 russet potatoes. Poke shallow holes 10 times into potatoes. Add about 1 1/2 cups water in pressure cooker so water is just below metal rack. Place rack in cooker. Lay potatoes on rack. Seal cooker and valve to lock. Set time for 20 minutes. Let pressure release naturally for 10 minutes. Then flip valve for quick release. Now season according to taste and eat.
My pressure cooker is an 8 quart size. If yours is smaller it might not accomadate 4 large potatoes. I using fewer medium potatoes I'd start with 12 minutes and see if that is enough time.