Place Objects on the scene

Unity Engine
1

Hello guys, im making a game(for school) and i have in mind to do a drag and drop objects into this kind of room hive(red square) and what is the best way to do it?

2

To point you in the right direction with one idea :

  1. Create some objects in 2d using Unity UI
  2. Make it so that the user can drag an 2d object by detecting where the object is dragged from and released.
  3. when released locate the point on the screen and use the camera to project a ray from the camrea to the room where
    the finger was released. Place the object in the room as a 3d object or as a 2d object.

You should be able to use the same principle for both 3d and 2d objects.