>>21171214 lb/pb
>How is it anons began using post numbers to decode when it was never mentioned or in the graphic?
Post numbers are arbitrary. Aggregator sites indexed the drops.
There are no valid decodes. Timestamps were used as authenticators until authentication was established.
There is no formal canon, just discussions on an obscure imageboard.
There is nothing binding some of the early drops except a shared theme and language. One signature in the first 35 or so posts (DJT), then some signed 'Alice & Wonderland', then 'Q', but it is apparent that more than one individual signed as 'Q'.