Add water to the inner pot and place trivet inside.
Place frozen ground beef on the trivet. (You can cook more than 1 pound at a time, but keep the meat in 1/2 pound or 1 pound chunks.)
Close and lock the lid, turning the steam release valve to closed. Press Steam (high pressure for 10 minutes) and then Start/Stop.
When the cooking cycle is done, allow a 5 minute natural pressure release and then open the steam release valve to release any remaining steam. Press Start/Stop.
Open the pot and lift out the cooked meat. Pour out the water and drained fat, Return the cooked meat to the pot and press Brown/Saute. Using a non-stick safe tool, break apart the meat into crumbles, being sure to cook out any remaining pink.