Creating Panning Buttons in C#

I am new to this and still trying to learn. I have a bunch of VBA code that I am trying to convert to C# and even the most basic things are hanging me up.

Currently I am trying to build a button that pans the display Left when pressed.

The original VBA code that I have looks as follows:

Sub pan_left()
On Error GoTo Errhandler


   Dim pMxDocument As IMxDocument
   Dim pactiveview As IActiveView
   Dim penv As IEnvelope
   Dim pxmax, pxmin, pymax, pymin As Double
   Dim nxmax, nxmin, nymax, nymin As Double
   Dim width, height As Double

   Set pMxDocument = ThisDocument
   Set pactiveview = pMxDocument.FocusMap
   Set penv = pactiveview.Extent

   pxmax = penv.XMax
   pxmin = penv.XMin
   pymax = penv.YMax
   pymin = penv.YMin

   width = pxmax - pxmin
   height = pymax - pymin
   nxmax = pxmax + (width / 1.08)
   nxmin = pxmin + (width / 1.08)
   nymax = pymax
   nymin = pymin

   penv.XMax = nxmax
   penv.XMin = nxmin
   penv.YMax = nymax
   penv.YMin = nymin

   pactiveview.Extent = penv
   pactiveview.Refresh

ThisDocument.fTimer
Exit Sub
Errhandler:
On Error Resume Next


End Sub

I have been trying to write it using the Desk top Addins. I have found some code on ESRI's website found here: Pan Left (Not sure if I am even on the right track.)

Currently my code looks as follows:

using System;
using System.Collections.Generic;
using System.Text;
using System.IO;
using ESRI.ArcGIS.Carto;
using ESRI.ArcGIS.Geometry;
using ESRI.ArcGIS.Controls;
using ESRI.ArcGIS.SystemUI;
using ESRI.ArcGIS.ADF.CATIDs;
using System.Runtime.InteropServices;
using ESRI.ArcGIS.ArcMapUI;
using ESRI.ArcGIS.Framework;



namespace NAIP_QQv1

{



    [ClassInterface(ClassInterfaceType.None)]

    [Guid("593EDF4F-D1FE-4a8d-8076-C3B583C37F6B")]



    public class PanDown : ICommand

    {
    #region COM Registration Function(s)
    [ComRegisterFunction()]
    [ComVisible(false)]
    static void RegisterFunction(Type registerType)
    {
        // Required for ArcGIS Component Category Registrar support
        ArcGISCategoryRegistration(registerType);

        //
        // TODO: Add any COM registration code here
        //
    }

    [ComUnregisterFunction()]
    [ComVisible(false)]
    static void UnregisterFunction(Type registerType)
    {
        // Required for ArcGIS Component Category Registrar support
        ArcGISCategoryUnregistration(registerType);

        //
        // TODO: Add any COM unregistration code here
        //
    }

    #region ArcGIS Component Category Registrar generated code
    /// <summary>
    /// Required method for ArcGIS Component Category registration -
    /// Do not modify the contents of this method with the code editor.
    /// </summary>
    private static void ArcGISCategoryRegistration(Type registerType)
    {
        string regKey = string.Format("HKEY_CLASSES_ROOT\\CLSID\\{{{0}}}", registerType.GUID);
        ControlsCommands.Register(regKey);

    }
    /// <summary>
    /// Required method for ArcGIS Component Category unregistration -
    /// Do not modify the contents of this method with the code editor.
    /// </summary>
    private static void ArcGISCategoryUnregistration(Type registerType)
    {
        string regKey = string.Format("HKEY_CLASSES_ROOT\\CLSID\\{{{0}}}", registerType.GUID);
        ControlsCommands.Unregister(regKey);

    }

    #endregion
    #endregion


    [DllImport("user32.dll")]
    static extern IntPtr SetFocus(IntPtr hWnd);


    private System.Drawing.Bitmap m_bitmap;
    private IntPtr m_hBitmap;
    private IHookHelper m_pHookHelper;


    public class Pan_Left : ESRI.ArcGIS.Desktop.AddIns.Button
    {

        public Pan_Left()
        {
            //m_pHookHelper = new HookHelperClass ();

        }

        protected override void OnClick()
        {//Get the active view
            IActiveView pActiveView = m_pHookHelper.ActiveView;

            //Get the extent
            IEnvelope pEnvelope = (IEnvelope)pActiveView.Extent;


        }

        protected override void OnUpdate()
        {
        }
        }
    }
}