How to combine Entities?

[Vipes]

To create such an effect, with accurate precision you'd need to use a specific entity. If you want books to fall from shelves you should use Khyrpa's way after you create that same entity.

I dont want the boos to fall, I want the whole thing to.

And I tried to do it like Khyrpa said. It's not working for me, it still wont combine.