Write down your word recovery seed in order, which could be a range from 12-24 words depending on your deterministic wallet.
You may have already backed this up using a different solution already.
Go to the official bip39 master wordlist for reference.
Your bip39 deterministic wallet is referencing this dictionary before encryption takes place (2048 words).
Each one of your seed words represent a number in the bip39 wordlist.
Choose the first word in your Mnemonic Phrase and look through the word list until you find it.
The number it is associated to is what we need. (e.g. 1 = abandon)
Write the number down and then do the same for the rest of the words. The numbers for each word will be the total that you need to add up when you punch in the dots with each corresponding phrase.
Once you are happy you can punch them in with a manual centre punch. This will make a permanent indentation in the steel card.
Repeat this process for the rest of the words in sequential order. A magnifying glass will help, please take your time.
Triple check all your numbers in each grid add up correctly!
Each Grid total needs to match your original word in sequential order that your deterministic wallet provided to you.
It’s worth testing that you can rebuild your wallet using the steel card you just created. Only then should you discard your other copy, unless this is a backup of a backup.
The two holes in the steel plates can be used in a variety of ways. You could bolt them together, put locks through them, use tamper tags, cable ties. Equally you could screw them to a permanent fixture face down somewhere discreet.
What are the additional dots for?
Each line has 26 dots which are the amount of characters in the english alphabet. You could make up a password (Dot 1 being A)or equally you could create a tricode for the cryptocurrency you have, e.g:‘BTC’ B = Dot 2, T = Dot 20, C = Dot 3 (this could be on the second line).
You will have noticed the steel cards go from 1-12 only. If you have 24 seed words then you could use the spare dots as card numbers so you know which sequence to enter them in. Our original designs were upto 24 but we thought this would be an additional security measure.