4.18-arcore-sdk-preview2 GenerateProjectFiles -Error

Hi,

I’m having a problem where this message

says that I seem to be missing some files that are required to generate the project files.

I’ve followed the instructions here: [ARCore SDK for Unreal Engine  |  Google for Developers][2].
I have no previous builds of UE and no Launcher installed. And no Android development setups yet.
I have VisualStudio 2015 and 2017 installed.

Am I totally missing something?

Any help would be greatly appreciated.