The Package is a designer-friendly tool that allows users to protect in game Components from being deleted when the game changes scenes. It manages all the backend work, which includes no duplication of the Game Objects once you return to the original scene which protects them.
Import The Package files from the Unity Asset Store. Drag The Package Manager prefab into your scene. That is, the first scene where your want to start protecting certain Components. Any scene that is loaded after that will contain these protected Components. Then drag the Components you wish to protect into your The Package Manager prefab's Protected Objects List. If you need more space in the Protected Objects List, just increase the list size. If you drag the same Component twice into the list there is no penalty for it.