One clue. Your first deduction.
What do you know for certain?
A short example from the first case, the theater case with three people.
If you get stuck, help comes in three steps: first the clues, then the cell, finally the sentence with its reasoning.
The file records: Harro Beil was not in the dressing room. And: Harro Beil was not on the stage.
Reveal the deduction
Harro Beil → box office
Three places were possible, and two are ruled out. That leaves the box office for Harro Beil. This is how the app guides your first deduction: it shows which clues belong together, and you enter the value yourself.