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.
You will need these numbers to punch in the dots for each section. There are 4 partitions per section (0-9).
There are a maximum of 4 numbers per section which match your word in the bip39 wordlist. For example if the first word is ‘abandon’ the number ‘1’ would be punched in the forth partition of the first section with 3 zero’s preceeding it (0001).
A manual centre punch will make a permanent indentation in the steel card.
Another example could be ‘zoo’ for the second word. This is number 2048 in the bip39 wordlist. Each number would be added in the four partitions of the second section (2048).
Repeat this process in sequential order. A magnifying glass will help.
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.
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.