Terrain having multiple textures

Hi!

I'm developing a terrain procedural generator with Unity.

The terrain generator is already done, but i dont know how to continue applying different textures to the terrain.

I want to have the hill-like terrain with grass texture, the sharper mountains with rocks texture and water and rivers with, of course, water texture.

I only know the way to apply an unique texture to the whole terrain:

 SplatPrototype[] tex = new SplatPrototype [TerrainTextures.Length];

 for (int i=0; i < TerrainTextures.Length; i++)
 {
     tex [i] = new SplatPrototype ();
     tex [i].texture = TerrainTextures [i];    //Sets the texture
     tex [i].tileSize = new Vector2 (1, 1);    //Sets the size of the texture
 }

 tData.splatPrototypes = tex;    // Apply texture

I can set many textures to the array in the Inspector, but this code only applyes the first.

Anyone can help with a sketch of code, please?

Thanks in advance.