Activate another open workbook and sheet

Not path but name, not workbook but Windows

Sub a()
 Dim Entry As String
    Dim Filepath As String
    Filname = "Cartel1.xlsx" 'Range("D6").Value
    Entry = "Sheet1" 'Range("D8").Value
    Windows(Filname).Activate
     Worksheets(Entry).Activate
End Sub