How to spawn a scenegraph entity prefab

I’m trying to add an entity_prefab to the scene on command, but this seems to be impossible. Does any of you a idea?

To give more insight. In short: The prefab is a supply drop that falls from the sky. When it landed You can open it. I want to be able to set a location and spawn it like you can with normal blueprints

Let me know if you have suggestions