Form1 On Show then button1 click

var
timer:TTimer;

procedure Form1_OnShow (Sender: TObject; Action: string);
begin
  timer:=TTimer.Create(Form1);
  timer.Interval := 10000;
  timer.Enabled := True;
  timer.OnTimer := @OnTimer;
end;

procedure OnTimer;
begin
Form1.Button1.Click;
timer.Enabled := False;
end;