The numbered tumblers rotate on the shaft or axle. There is a slot in the shaft that enables the selection of specific numbers so that you may choose any combination of numbers when setting your code.   To determine what the numbers were set on (in case you
forgot the numbers that you originally selected, or if they've been accidentally reset) just push or hold the tumblers to the side of the casing to enable you to view inside of the lock. Start turning the tumblers until you can see the slot appear on the shaft. Once you have done this on all three tumblers then that will be the numbers originally selected and will unlock your case.