There are a few different ways that you can open your Mesa safe. The most common way is to use the key that came with your safe. If you don't have the key, you can usually find it by looking in the owner's manual. If you still can't find the key, you can try using a paperclip or other small object to push the reset button on the back of the safe. This will usually open the door. If none of these methods work, you may need to contact Mesa customer service for help.