Learn a bunch of new tricks with this tutorial from Wysilab. 

Wysilab, the creators of Instant Terra, published a video that covers the process of importing and setting up terrains in Clarisse.

The first step is to generate a terrain in Instant Terra, of course, which can be used for your scene. Then, this terrain is exported as a mesh, plus different masks are also exported. You need to import all the data into Clarisse. Please note that textures are applied automatically based on the different masks.

Want to learn more? You can get the Instant Terra project and the Clarisse project to play and study them here.