Tutorials for using river tool?

Hello,

I just upgraded my World Machine finally so I could get the new river tool. However, I am clueless on how to use it. I can find nothing on the forums or elsewhere. Nothing in the manual, and nothing in the example projects. Is it not being developed anymore?

My purpose was to upgrade to Pro and then add Geoglyphs but I really want to try the river tool first.

Any suggestions on where I can find some help?

Thanks.