Splatmap Importing

...doesnt allow me to add splat maps. It only allows me to import from the current selected terrain, which has no splat maps.

There seems to be a bug
https://www.raywenderlich.com/21911888-using-the-terrain-tools-in-unity#toc-anchor-019

According to this tutorial, it seems there should be the ability to add splatmaps.

Unity 2020.3.29f1
Terrain Tools 3.0.2-preview.3

 

anyone?