Choose a page
Pick a page of this site, or bring a copy of a page's plain text that thou keptest thyself.
Find it in a seal
The fingerprint (its SHA-256) is looked for in every sealed list, newest first. A page changed since its last seal will not be found until the next one.
Work the proof down to Bitcoin
The sealed list is fingerprinted, and its proof (an OpenTimestamps file) is worked step by step to a Bitcoin block. Then compare the last number with that block on an explorer thou trustest.
What this proves, and what it does not
It proves that the page's words, exactly as they are, were in a list that existed by the time of that Bitcoin block, and that the list has not been changed since. It does not prove the words are true, and it does not prove who wrote them. All the arithmetic runs here, in thy browser; the files come from this site, and thou mayest download them and check them with any OpenTimestamps tool instead (opentimestamps.org). Every seal is listed in /seals/seals.json.