Creating a Unity prefab is simple and straightforward. Create a Game Object in the scene and drag it into the Project View to create a prefab from the GameObject. This Game Object and all its children are now saved as a prefab asset and can be reused throughout your project.
You can add this new prefab asset to your scene by dragging it from the Project View into the Scene View or Hierarchy Window. This will add a new prefab instance to your scene. The prefab instance in the scene is just a reference to the prefab asset, and all its data is stored in the asset.