Automated processing

Like this -

Dim MainFN as String

MainFN = Application.GetOpenFilename(FileFilter:="All files (*.*), *.*", Title:="Please open the file")
If MainFN = "" Then
      
    MsgBox "You have not selected a file."
    GoTo proceed
         
Else
     
    Workbooks.Open Filename:=MainFN
    MainFN = ActiveWorkbook.Name
    
End If