Auto Open macro

How do I get a macro to start when I open a workbook? I have the following code that works fine when I run it. Any help would be appreciated. Thank you in advance.

Option Explicit
Public setDate As Date
Sub UpdateTime()
    setDate = Now() + TimeValue("00:00:30")
    Application.OnTime setDate, "TimeUp"
    ActiveWorkbook.Save
End Sub

Hi Siray,

In the VBA Editor, double-click on the ThisWorkbook module and insert a line of code in the Workbook Open event to call your macro, e.g.

Private Sub Workbook_Open()
Call UpdateTime
End Sub