First of all i want to thank you in advance :)

I don't have any experience in VBA (only coded a few lines in Python and Java a few years ago) but got the task to create a macro that creates a new sheet where are stored the current calendar week + the week 3 weeks after in it. e.g.: Steuerliste_neues_System_KW_25-28.xlsx

Currently I'm not able to get even the current week in it...

This is my current code:

Sub Main()
kw_ermitteln
End Sub

'Kallenderwoche ermitteln
Public Sub kw_ermitteln()
    'kw = DINKw("DD.MM.YYYY")
    kw = DINKw(Range("I1"))
    Dim kwString As String
    kwString = CStr(kw)
    Workbooks.Add
    ActiveWorkbook.SaveAs Filename:=".../Steuerliste_neues_System_KW_" + kwString + ".xlsx"
    ActiveWorkbook.Close


End Sub
'Function zur ermittlung der KW
Function DINKw(dat As Date) As Integer
    Dim kw As Integer
    kw = Int((dat - DateSerial(Year(dat), 1, 1) + ((Weekday(DateSerial(Year(dat), 1, 1)) + 1) _
    Mod 7) - 3) / 7) + 1
    If kw = 0 Then
        kw = DINKw(DateSerial(Year(dat) - 1, 12, 31))
    ElseIf kw = 53 And (Weekday(DateSerial(Year(dat), 12, 31)) - 1) Mod 7 <= 3 Then
        kw = 1
    End If
    DINKw = kw
End Function

But my problem with it is, that the new Excel data will just be named Steuerliste_neues_System_KW_.xlsx

I'm ready to learn so thanks again.