In the rubber pressing room the uncured rubber is molded or pressed into hot metal molds.  The outsole bottom molds are like big waffle irons.  The uncured cut rubber parts are laid in by hand then squeezed shut by a heated hydraulic pressing machine.  Inside the mold the uncured rubber flows to fill the mold while the heat causes the rubber to vulcanize.  This transforms the taffy like parts to become the tough flexible rubber sneaker bottom.