Yes, I will of course follow up with some tips one by one, as I said earlier, the reverse derivation is not difficult, the point is to understand the forward process.

I just wrote a paragraph to explain why this puzzle challenge exists.
This card was originally designed as a multi-table substitution encryption for generating multiple high-strength passwords, initially as a one-to-two mapping.

But that's not safe enough if it's going to be used for seed phrases, so this time I've upgraded to a set of two cards, and as you can see, for each index letter, that now translates to four possible substitutions, which is a one-to-four multi-table substitution.

Think about it differently, what would you do if you were the one using such a one-to-four multi-table substitute encryption?
Would you leave yourself a hint: in what way should these two cards be placed? And in what order to use the four substitution tables once they've been placed?