Purchased for the first time a container of "pork and vegetable buns" at Kam Man in NYC from the refrigerated case that has the fresh noodles etc. How are they prepared? I know there are different variations, this one is a large, doughy white bun, pinched at the top, about 3" in diameter. Has a small piece of paper stuck to the bottom of each. Do I steam them, and if so, for how long?