Add formulas to specific cells

Question

I'm creating a macro where I could apply my formulas to selected column (this is the working month-year, example Nov-2022). I have initial code where the specific column for that month will be selected however I'm stuck as to what code I can use to apply the formula that will start and apply to row 11 to row 17 and row 20 to row 26 of that selected column. Do you have any codes where I can apply the formulas to these selected cells?

Codes to Find the Column selected in drop down (Month-Year):

Sub FindAddressColumn()
'Updateby Extendoffcie
    Dim xRg As Range
    Dim xRgUni As Range
    Dim xFirstAddress As String
    Dim xStr As Variant
    On Error Resume Next
    xStr = Range("C5").Value
    Set xRg = Range("D8:AA31").Find(xStr, , xlValues, xlWhole, , , True)
    If Not xRg Is Nothing Then
        xFirstAddress = xRg.Address
        Do
            Set xRg = Range("A1:P1").FindNext(xRg)
            If xRgUni Is Nothing Then
                Set xRgUni = xRg
            Else
                Set xRgUni = Application.Union(xRgUni, xRg)
            End If
        Loop While (Not xRg Is Nothing) And (xRg.Address <> xFirstAddress)
    End If
    xRgUni.EntireColumn.Select
End Sub

Formulas that needs to apply:

My range below is specific to Column N since my working month is placed in Column N.

How will I change the formula so it will be dynamic, for example I would like to work for December which is placed in Column O? Same formula but different Column.

    Range("N9").Select
    ActiveCell.FormulaR1C1 = _
        "=IFNA(VLOOKUP(RC[-12],'Working File'!C[21]:C[22],2,0), "" "")"
    Range("N10").Select
    ActiveCell.FormulaR1C1 = _
        "=IFNA(VLOOKUP(RC[-12],'Working File'!C[21]:C[22],2,0), "" "")"
    Range("N11").Select
    ActiveCell.FormulaR1C1 = _
        "=IFNA(VLOOKUP(RC[-12],'Working File'!C[21]:C[22],2,0), "" "")"
    Range("N12").Select
    ActiveCell.FormulaR1C1 = _
        "=IFNA(VLOOKUP(RC[-12],'Working File'!C[21]:C[22],2,0), "" "")"
    Range("N13").Select
    ActiveCell.FormulaR1C1 = _
        "=IFNA(VLOOKUP(RC[-12],'Working File'!C[21]:C[22],2,0), "" "")"
    Range("N14").Select
    ActiveCell.FormulaR1C1 = _
        "=IFNA(VLOOKUP(RC[-12],'Working File'!C[21]:C[22],2,0), "" "")"
    Range("N15").Select
    ActiveCell.FormulaR1C1 = "=SUM(R[-6]C:R[-1]C)"
    Range("N18").Select
    ActiveCell.FormulaR1C1 = _
        "=IFNA(XLOOKUP(""Total Fixed Fee / System Implementation Current WIP to Bill"",Current!C[-13],Current!C[-3],),"" "")"
    Range("N19").Select
    ActiveCell.FormulaR1C1 = _
        "=IFNA(VLOOKUP(RC[-12],'Working File'!C[25]:C[26],2,0),"" "")"
    Range("N20").Select
    ActiveCell.FormulaR1C1 = _
        "=IFNA(VLOOKUP(RC[-12],'Working File'!C[25]:C[26],2,0),"" "")"
    Range("N21").Select
    ActiveCell.FormulaR1C1 = _
        "=IFNA(VLOOKUP(RC[-12],'Working File'!C[25]:C[26],2,0),"" "")"
    Range("N22").Select
    ActiveCell.FormulaR1C1 = _
        "=IFNA(VLOOKUP(RC[-12],'Working File'!C[25]:C[26],2,0),"" "")*-1"
    Range("N23").Select
    ActiveCell.FormulaR1C1 = _
        "=IFNA(VLOOKUP(RC[-12],'Working File'!C[25]:C[26],2,0),"" "")*-1"
    Range("N24").Select
    ActiveCell.FormulaR1C1 = "=SUM(R[-6]C:R[-1]C)"
    Range("N25").Select
End Sub

Answer 1

I would use a loop and reletive location i.e.

Sub Macro1()
    Dim Counter As Integer
    Counter = 1

    Do While Counter <= 12
        ActiveCell.FormulaR1C1 = Counter
        ActiveCell.Offset(0, 1).Range("A1").Select
        Counter = Counter + 1
    Loop
End Sub