Unreal Engine 4.12.3 Foliage Issue

I am getting the hang of creating videos discussing my issues with the latest release of Unreal Engine 4 and
creating videos talking about what I am having issues with:)
I am trying to place a bunch of boulders in my scene using the Foliage tab. It is not working for some reason.


You may want to report it as a bug over on the answerhub: answers.unrealengine.com

That way a technician can look into it and see what has happened or if there is a way to fix it.