There are a few things you need to know before opening a Febreze car air freshener. First, make sure that the car is in the correct position for the Febreze car freshener. Second, unscrew the top of the car freshener and remove the cartridge. Third, insert the new cartridge into the empty space on top of the old cartridge. Fourth, screw back on top of the car freshener and screw in place. Fifth, turn on your car’s air conditioning and enjoy your fresh scent!