I am completely new to Unity 3D. I own the free version. For my first project, I am trying to make a MineCraft like clone. I followed tutorials, but now i'm trying to change something so it works how I want it. First off, how can I place a cube with a texture on it? Here's a chunk of code where I need to be able to do this:

   function Build() { 
    if (HitBlock()) { 
    var cube = GameObject.CreatePrimitive(PrimitiveType.Cube); 
    cube.transform.position = hit.transform.position + hit.normal; 
    } 
    }

This spawns a default cube with no texture whatsoever. How do I get a texture?

Next, how to I add an arm that follows me around with animation. I know I have to parent it to First Person Controller > Main Camera... But, what do I do for animations? And I have a gun, but I want it only to appear when I press a key, or press a key to get rid of this.

Third, for deleting a brick, how can I force the user to click, but hold down for X amount of time before the Cube breaks? I have an instant delete chunk of code here:

 function Erase() { 
if (HitBlock()) 
Destroy(hit.transform.gameObject); 
}

I know absolutely NO javascript, or java, so I came here.