Changing the texture of a certain area?

This is probably explained in 100 different places, but how to change the texture of a certain area? Like making a mountain stone, but the rest of the map grass? Thanks in advance!

Do you mean that you have a landscape and you want to paint on to it with different textures?

(first minutes)

Ok, saw you 2nd thread in the rendering section. I will close this one now :slight_smile: