Just found these - I believe them to be correct. If they don't work, I'd just give Stack On a call. Good luck!
1. Locate the small red red button on the inside of the door near
the hinge.
2. Press the red button and then release it, you will hear a beep. The yellow light on the faceplate will be activated and will stay on for a
period of time that should allow you to enter your code. You can only enter your code while the yellow light is on.
With the door open and the yellow light on, enter your own personal security code, which can be 3 - 8 digits long, and confirm your new code
by pressing the " " symbol on the electronic touch pad. Before you close the door, try the new security code to make sure the lock
releases the handle so you can turn it and retract the live action bolts. DO NOT SHUT THE DOOR UNTIL YOU HAVE CONFIRMED THAT
YOUR NEW SECURITY CODE HAS BEEN ENTERED CORRECTLY.
If the code fails, go through steps 1 and 2 again. If the code works successfully record your combination number on the front of this form or
somewhere in your records, then you should lock the safe.
When you open the safe in the future enter the security code you have set followed by the " # " symbol.