How can I import the Content from the "Valley of the Ancient" Demo to my Project?

Hey there,
i´d like to know if theres any way to import the Content espacially the Rocks to my own Projekt.
I tried to download it and migrate it but then i can see the content with a picture down in the content browser but then I add it to the level and I cant see anything. Are there other ways to do this?

Ok just a short Update:
I just imported my old Project to the Acient Valley Pack