Application Object In Access

[DannyDont]

I have a routine that I run in the On Open event in Excel. It creates a backup of the file with the came name, directory, etc. but as a Date and Time to the file name. This is a very handy way "for me" to recovery from my self imposed disasters, I am supposed to put the code in the text area. I am not sure where that is. Not finding that I will carefully submit my current Subroutine, The issue that I am having is with With.ThisWorkBook and Application.WorksheetFunction. What are the corresponding values for Access. I have found where to put the code, I now just need to know what code to put there.

Please explain what I need to do to get to the Text Area or whatever,
here is the code:

Private Sub Workbook_Open()
    Dim sFileName As String
    Dim sDateTime As String
    With ThisWorkbook
        sDateTime = " (" & Format(Now, "yyyy-mm-dd hhmm") & ").xlsm"
        sFileName = Application.WorksheetFunction.Substitute (.FullName, ".xlsm", sDateTime)
        .SaveCopyAs sFileName
    End With
End Sub

Thank you for any help you might provide and also "tell me where to go" on the Text Area feature.
DannyDont