To make ribs in your slow cooker, add ½ cup of water or broth to the slow cooker after seasoning your ribs, then insert the meat, followed by chopped onion and garlic. With the slow cooker set on high, the fatty cuts of meat should be done in a little over four hours, then slather them in barbecue sauce and roast for another 10 minutes in the oven so that the sauce can become a glaze.