On the game board you will see the following clues
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What the clue tells you is first, that it is a Polybius Square, which is encoding letters with numbers:

The three grids also are a clue for what to do with the letters on the poster.
On the game board you will see the following clues
![]()
![]()
![]()
What the clue tells you is first, that it is a Polybius Square, which is encoding letters with numbers:

The three grids also are a clue for what to do with the letters on the poster.