How to keep my board in the center for different screen size in Unity3D?

I am developing a board game. My board is created dynamically using C# script like so

    /// <summary>
    /// Draws the board of the figure. Call the Load event of the form.
    /// </summary>
    public void DrawingBoard()
    {    
        CubeDark.transform.localScale = new Vector3(3f,2f,3f);      
        CubeLight.transform.localScale =  new Vector3(3f,2f,3f);
        for(int i = 0; i < _boardSize; i++)
        {
            for(int j = 0; j < _boardSize; j++)
            {
                if((i+j)%2 == 0)
                {
                    UnityEngine.Object.Instantiate(CubeDark,new Vector3(i*3,_boardHeight,j*3), Quaternion.identity);    
                }
                else
                {
                    UnityEngine.Object.Instantiate(CubeLight,new Vector3(i*3,_boardHeight,j*3), Quaternion.identity);
                }
            }
        }           
    }

Screenshot:

What I want to do now is to scale the camera in order to put the board in the center of the screen ( no matter what size of screen ).

What I have tried so far is to attach the below script to my camera GameObject.

using UnityEngine;
using System.Collections;

public class PositionCamera : MonoBehaviour {

    public float fWidth = 2.0f; // Desired width
    void Start () {
        float xFactor = Screen.width / 1024f;
        float yFactor = Screen.height  / 768f;          
        Camera.main.rect=new Rect(0,0,1,xFactor/yFactor);

    }
}

But unfortunately, it didn't work. A part of the board still does not appear.

So here come my questions:

• How can i keep my board centered for different screen resolution and for different platforms ( android and standalone )?


• How can i make my game window resizable when building my unity project?


• For android platform, Why does only half of the screen show the game?

Thanks.