Familiarizing yourself with your digital safe
Before you start modifying your safe, you should read the instructions which came with it and ensure you know how to set a combination and open/close it etc.
However, you should then set the combination to '1'. On your safe that may mean '1' followed by 'A' or followed by '#'. Or perhaps '111' if your safe has a minimum combination length of 3. When the safe is under control of the MortiSafe Pro core unit (ie you're not allowed to open it) the combination won't open the safe, so it doesn't matter how long or short the combination is. The combination isn't part of the security of the system, but you will need it to open the safe when the MortiSafe Pro core unit will allow you to.
However, I know of one MortiSafe user who likes multiple levels of security, so he uses a MortiSafe but also uses a long safe combination which is encrypted by a different method (and a locked box inside the safe too). Whether you use a short or long combination is up to you.
Note that, even though the MortiSafe Pro core unit has a power supply of its own, you still need to keep the batteries that are in the safe as they power a different circuit.