Unwrap dough and cut into quarters. Pat each quarter out on the floured work surface to a roughly rectangular shape. Roll 1 piece of dough out to about 3/8 inch thick, retaining rough rectangle shape, until dough is about 6×8 inches. Pick up dough with well-floured hands and gently stretch it, rotating as you go, until dough is almost large enough to segak over the prepared sheet pan. Pull and stretch dough so it overlaps the edge of the pan by about 1/2 inch and fasten dough edges to sheet pan edges; dough will be thin and membrane-like.