Start with records, not isolated squares
Each ClueRelay case describes four records. A record contains one entry from each of three categories: a person, an item and a position in a four-slot order. Every entry is used exactly once. This rule matters as much as the printed clues. If one person has the brass compass, no other person can have that same compass, and that person cannot simultaneously have a different exhibit.
The three grids show all category pairs. They are different views of the same four records, not three independent puzzles. A match between a person and an exhibit, together with a match between that exhibit and a slot, links the person to that slot as well. Write only deductions that you can justify from the notes and the one-to-one rule.
Use all three cell states deliberately
A question mark means that you have not decided the relation. A cross means the two entries belong to different records. A check means they belong to the same record. Clicking cycles through these states. Keyboard players can use X, Y and Delete to choose the intended state directly. Matches do not silently fill other cells, so the board remains a record of your actual decisions.
A clue that says earlier does not necessarily mean immediately before. An immediately-after clue does require neighboring slots in the stated direction. A neighboring-slots clue allows either order. Read this distinction before marking exclusions; it is a common source of avoidable contradictions.
Check an inference, then finish the case
Check deductions asks whether at least one complete arrangement can satisfy the clues and your current marks. A consistent result does not complete missing entries for you. If a conflict appears, the explanation identifies a set of clues and marked relations that cannot all be true. Use Undo or clear the relevant marks and reconsider the inference.
You finish by marking all twelve matching pairs across the three grids without contradicting the solution. Exclusions help you work, but they are not required in every remaining square. After completion, compare the reconstructed records and inspect your action history. The goal is a justified chain of deductions, not an unverified speed score.