Remove the coverings that cover the hinges on the freezer and remove the screws in the hinges. Depending on the types of hinges, remove the screws with a screwdriver, a nut driver or a socket wrench.
Put a level on the top of the freezer door and adjust the door until it is level. You can tell when the door is level when the air bubble in the level is directly between the two red or black lines.
Place the screws back into the hinges with the freezer door staying level and replace the coverings.
Take out the screws that hold on the freezer door's rubber gasket. This is the part of the door that seals it closed. Peel off the interior rubber gasket on all sides of the freezer door.
Apply a new gasket with adhesive backing on all the sides of the door that you removed it from. Make sure to slide it underneath the metal gliding strip.
Put the screws back onto the new gasket tightly to secure it into place.