How do I load another texture to the gameObject?

Questions & Answers
1

Example

if(number > 0 && number <20)
{
// Here I want to change the texture
}

I must show the way of the texture? I do not know how to do, help! Sorry My bad english!

2

Usually the easiest way is like this:

Texture2D newTexture;

...

// change the texture on only this object:
if ( number > 0 && number < 20 ) {
  renderer.material.mainTexture = newTexture;
}

// change the texture in the material:
// (this will affect all objects with this material)
  renderer.sharedMaterial.mainTexture = newTexture;

More details on the Material page.