Steelwallet is an offline, metal seed storage tool that protects your seed against fire, water, electrical-shocks and corrosion. It consists of engraved stainless steel sheets and an automatic puncher. Each sheet can store 12 seeds word, 6 per side.
All words of your seed come from the BIP-39 word list. One property of that wordlist is, that by knowing the first 4 letters you identify each word unanimously. That’s why you can only punch the first 4 letters of each word on your Steelwallet.
For example, if your first word is “escape”, make a mark where column 1 and row E cross. Continue with the first 4 letters of each word.
Before you use the automatic puncher you should verify that you’ve marked all spots correctly.
After having punched the first 6 words, turn the sheet around and punch the next 6 words. Repeat until you’ve punched your whole seed.
Once you have finished setting up your Steelwallet, make sure to store it in a safe location.