How do you hook up 1968 chev C10 327 ci heater hoses?

It matters if it has ac or not. If it is a non ac vehicle, the hoses and coolant flow from the fitting close to the thermostat housing to the lower heater core tube, then out the upper heater core tube to the fitting on the water pump. If it has ac, the hose from the upper heater core tube connects to the fitting on the radiator.