Set the lock to the initial position "0-0-0". This is the factory setting the lock comes with. Make sure all three numbers are set to zero before continuing.
Make sure the zipper pull is not in the lock. The zipper pull must be free and not stuck so that the lock can be set correctly.
Take a pen or a thin object and press the red button next to the numbers. This button puts the lock in programming mode.
Hold the red button down continuously while setting the new combination. Do not release the red button while turning the numbers.
After you have set the desired combination, release the red button. Make sure to check that the new code works properly before closing the lock.