I’m trying to paint some rocks at the terrain, but when i have to pick a texture for the rocks, these are the files that i can choose. 
I downloaded some rock textures from the official assets shop.
:idea: I own the free version and i’m using Windows 8.
If you want to add rocks as meshes, prepare your rocks as a prefab with textures etc and then you can select them in the detail mesh window.
In case you just want to have rock textures directly on your terrain, you can add the texture in the fourth category of the editing tools of your terrain.
i should “make rocks” as assets and then i will be able to select them ?.
The thing that confuses me is why is there: a constructor model, a skybox, etc. Instead of the rock models that i downloaded.
PD: sorry if my english is not perfect, is not my main language.