Grass on terrain

Hi, I created the plants simply as a quad2d, now I want to put them down on the ground in a random but respecting the other members on the scene, for example, lake, house etc.
Also if possible I would like them to be positioned at different heights, of course, attached to the ground.
The land I created from sceneEditor, surely the issue has been examined but not found anything that explains step by step or in general.

You can tell you what to read, advice or other?

I thought about creating a regular polygon, which is very complicated …

PS: If discussion is in the wrong section, My apologize.