Timer to move file from one dir to another dir

I want to transfer one file for every seconds from one dir to another dir.

I have a timer but it's not working.

During button click is transferring one file & another click it's transferring another file. 

How can i transfer one file for every 3 seconds by using the timer?

Code:

  private System.Timers.Timer MyTimer;
 private void bStart_Click(object sender, RoutedEventArgs e)
        {

                string targetPath = @"C:\Test\HFP\Prints\3_5x5\";
                if (!Directory.Exists(targetPath))
                {
                    Directory.CreateDirectory(targetPath);
                }
                DirectoryInfo dirInfo = new DirectoryInfo(targetPath);
                if (dirInfo.Exists == false)
                    Directory.CreateDirectory(targetPath);

                List<String> myImages = Directory
                                   .GetFiles(destination_dir35x5, "*.*", SearchOption.TopDirectoryOnly).ToList();

                
                int i = 0;
                MyTimer = new System.Timers.Timer();
                
                MyTimer.Interval = 3000;
                MyTimer.Start();
                MyTimer.Enabled = true;
                
                    string file = myImages[i];

                    FileInfo mFile = new FileInfo(file);
                    if (new FileInfo(dirInfo + "\\" + mFile.Name).Exists == false)
                        mFile.MoveTo(dirInfo + "\\" + mFile.Name);

                    i++;
                b35x5Stop.IsEnabled = true;
                b35x5Send.IsEnabled = false;
        }
//Button to stop the timer
	private void b35x5Stop_Click(object sender, RoutedEventArgs e)
        {
            MyTimer.Stop();
            b35x5Send.IsEnabled = true;
        }