Open the unit using the release button on the right side, then tighten the film cartridge by rolling the white film cartridge shaft towards the back of the unit. Make sure that the two white ends of the film cartridge are closest to the rear of the machine and that the two blue ends are closest to the front of the machine. Also, please check that the film feeds from the top of the white rollers to the bottom of the blue rollers. If there is no film on the white roll, that means that the fax machine is out of film and needs a replacement film roll. Please check the operating instructions for specific installation instructions for your particular fax machine.