Any numbers or letters on the dial, or around the dial?
I've seen various approaches of four number combination instructions. For example, here are the Sargent & Greenleaf instructions for a four combination lock:
1. Starting anywhere, turn the dial right (clockwise), stopping when the first combination number comes to
the opening index the FIFTH time.
2. Turn the dial left (counterclockwise), stopping when the second number comes to the opening index the
FOURTH time.
3. Turn the dial right, stopping when the third number comes to the opening index the THIRD time.
4. Turn the dial left, stopping when the fourth number comes to the opening index the SECOND time.
5. Turn the dial slowly to the right until it comes to a positive stop, indicating the bolt has retracted.
If the last number is a 0 (zero), it is a three number lock.
http://www.sargentandgreenleaf.com/pdf/630-146_8400_op.pdf