Refill the radiator slowly to minimize trapping air, and turn your heater on to let the coolant circulate and fill the heater core. After the car is up to normal temp. Shut it off, and when it's cool open the radiator cap and top it off if needed. Any air should have worked it's way out of the system and purged it's self. Then adjust the overflow bottle as necessary. Be careful opening a hot radiator.