Every Pathway card has an Effect (A) and an Activation Cost (B) written on it. They also have flavor text (C), but this doesn't affect gameplay. Until the Pathway card is activated by paying its cost, the card does nothing. The group may hold on to any inactive Pathway cards as long as they want.
When a prisoner is ready to activate a card, they do it at the start of their turn instead of MOVING or STAYING. To activate a Pathway card the prisoner/group must be able to pay the cost indicated on the card. After paying the cost, the card's effect is in play. Some cards will resolve immediately and some will have ongoing effects.
Discard Pathway Cards after activating them unless they tell you to keep them as reminders of their Cost/Effect.
NOTE: If you are playing without the Shrieking Hollow, a prisoner must LAND before they can activate a Pathway card.