Как добавить в приложение форму регистрации

{$apptype windows}
{$reference 'System.Windows.Forms.dll'}
{$reference 'System.Drawing.dll'}
 
uses
  System.Windows.Forms,
  System.Drawing;
 
procedure RegButClick(sender: object; e: System.EventArgs);
begin
  Form.ActiveForm.Close();
end;
 
begin
  Application.EnableVisualStyles();
  
  var MainForm := new Form();
  MainForm.Size := new System.Drawing.Size(500, 500);
  MainForm.StartPosition := FormStartPosition.CenterScreen;
  
  var RegForm := new Form();
  RegForm.Size := new System.Drawing.Size(250, 200);
  RegForm.StartPosition := FormStartPosition.CenterScreen;
  
  var l1 := new &Label();
  l1.Location := new System.Drawing.Point(10, 20);
  l1.Text := 'Login:';
  
  var t1 := new TextBox();
  t1.Location := new System.Drawing.Point(l1.Right + 10, l1.Top - 3);
  
  var l2 := new &Label();
  l2.Location := new System.Drawing.Point(10, 70);
  l2.Text := 'Password:';
  
  var t2 := new TextBox();
  t2.Location := new System.Drawing.Point(l2.Right + 10, l2.Top - 3);
  
  var b := new Button();
  b.AutoSize := true;
  b.Text := 'Sign in';
  b.Location := new System.Drawing.Point(75, 120);
  b.Click += RegButClick;
  
  RegForm.Controls.Add(l1);
  RegForm.Controls.Add(t1);
  RegForm.Controls.Add(l2);
  RegForm.Controls.Add(t2);
  RegForm.Controls.Add(b);
  RegForm.ShowDialog(MainForm);
  
  Application.Run(MainForm);
end.