Determine what kind of personal safe you have. The most common kinds of safes are keyed safes, combination lock safes and keypad lock safes.
Keyed safes will have a keyhole on the front. Insert your key as with any other keyhole, and turn. You may need to turn the key several times to reset all the tumblers in the lock and open the safe.
Combination lock safes will have a combination dial on the front that looks something like the combination padlocks most children use on their lockers at school. Rotate the dial clockwise to the first numeral of the combination, counterclockwise to the second numeral, and clockwise again to the third numeral--continuing to alternate rotation clockwise and counterclockwise if your combination has more than three numerals. When the combination is entered correctly, the latch should open.
Keypad lock safes will have a digital or mechanical keypad mounted somewhere on the front of the safe. Often, there will be a clear button, or a button with a pictograph of a key on it. Press this button first, and then enter your combination. Mechanical safes should open right away. Digital safes may require you to press the "key" button again before they open.
If you have lost the keys or combination to your safe, contact the makers of the safe for instructions on how to open it. Generally, you will have registered your safe with the manufacturer when you bought it. The manufacturer will be able to verify your identity and either replace your keys or tell you how to reprogram the combination.