First start by "clearing" the lock by turning it clockwise past zero AT LEAST TWICE.
Then, going clockwise, go to your first number.
now go counter clockwise, past zero once, to the second number.
If the secon number is very high or very low you might have to go past zero twice or not at all (but this is rare).
If you do it very gently you should be able to feel the second plate picking up arround zero - 10 usually.
now, go strait to your last number.
and voila!
combination locks work by having three notched plates, the notches in the plates must line up for the lock to open.
If you are gentle you can feel where it switches from being one plate to the next (it'll be a heavier dragging feeling as opposed to a free spinning feeling) and infact if you havent "picked up" the next plate yet you can actually go back and change the previous number.
you can also usually "feel" all teh notches in the last plate (by pulling slightly on the lock and noticing which numbers the lock buckles on) Even though there will be many notches in the outer plate (to throw off lockpickers) you can usually determine the last number by feeling which notch is slightly irregular. for example each time it buckles it allows a slight wiggle to the left or right, but on the correct number it'll have a slight wiggle room in the opposite direction.
Other fun facts about combo locks:
-all the numbers must be even or all numbers must be odd. If you have a lock with a mixed odd and even combo then it is a typo.
-the first and the last didgits can be found by adding 4
ex: If the first number is 0 then the last number is 0, 4, 8, 12, 16, 20, etc
If the first number is 23 the last number will be 23, 27, 31, 35, etc, all the way arround the lock back to 23.
If the last number is 08, then the first number is 0, 4, 8, 12, 16, 20, 24, 28 etc
-the middle number will follow the same pattern of adding 4, but will be 2 off
ex. first number 25, second number = 25 +2 = 27, 31, 35, 39 etc.
I hope this helps.