Briefcase Manufacturer

I recently bought a used briefcase combination lock at a garage sale. He is in wonderful condition and the lock works perfectly. It is set by default it is the combination of the manufacturer of all zeros. How do I reset the combination to my favorites?

Okay, well I'm just a kid and I always wanted a towel I do not know why, but I could not understand. but I went inside the other side of the numbers must be a piece of metal that you can push. hold it in and roll all of your desired code numbers.
well thats just the way my briefcase is that I do not know yours, but the best.
-Ardrya