Mystery Case Files: Key to Ravenhearst
In the game, "giving a piece" usually refers to finding specific inventory items to place into mechanical puzzles or dioramas that act as keys.
Enemies:
Beware of Ghouls and juiced-up prisoners who roam these areas.
Conclusion
If you are currently playing Mystery Case Files: Key to Ravenhearst and are stuck looking for specific keys or inventory items: