create a terrain. create an object. Select the terrain and note the small icons next to it. There is now one that is an "I" click it and you will be in the Instancing Lab.
there are no directions for this, so play around.
That thread up above to DAZ, I put a couple of tips

Quote - I can't find the instancing lab ????

Humankind has not woven the web of life. We are but one thread within it.
Whatever we do to the web, we do to ourselves. All things are bound together.
All things connect......Chief Seattle, 1854