Plotting multiple arrays on same graph

I am a little confused about how I should plot arrays. I am often confused with Charts and Chart Objects. I would like to pass arrays into a function that plots the arrays. In the main code getPlots I would like to make each column an array and divide it by the first column/array (I also need the first column divided by itself). In the plotting function, I often have an invalid parameter error, but I think my confusion comes from whether I am dealing with charts or chart objects. It happens in the plotting function in the line that says with activechart...

I should add that the timeArray represents the x-values.

Private Sub getPlots_Click()

    Dim numberOfRows As Integer
    Dim rowRange As Range
    Dim i, m, seriesIndex As Integer
    Dim firstArray() As Variant
    Dim secondArray() As Variant
    Dim timeArray()    As Variant
    
    If ActiveSheet.ChartObjects.Count <> 0 Then
        ActiveSheet.ChartObjects.Delete
    End If

    i = 5 'column number
    seriesIndex = 1
    
    Set rowRange = Range(Cells(8, i), Cells(Rows.Count, i).End(xlUp))
    numberOfRows = rowRange.Rows.Count + 7
    firstArray = Range(Cells(9, i), Cells(numberOfRows, i)).Value
    timeArray = Range(Cells(9, 4), Cells(numberOfRows, 4)).Value
    
    If ActiveSheet.ChartObjects.Count = 0 Then
        ActiveSheet.Shapes.AddChart.Select
        ActiveChart.ChartType = xlXYScatterLines
     End If
    
    While Cells(8, i) <> ""

        Set rowRange = Range(Cells(8, i), Cells(Rows.Count, i).End(xlUp))
        numberOfRows = rowRange.Rows.Count + 7
        

        secondArray = Range(Cells(9, i), Cells(numberOfRows, i)).Value

        Call createPlot(firstArray, secondArray, timeArray, seriesIndex)
        i = i + 1
        seriesIndex = seriesIndex + 1
    Wend


End Sub

Function createPlot(firstArray As Variant, secondArray As Variant, timeArray As Variant, seriesIndex As Integer)

    Dim normalizedArray() As Variant
    Dim array1() As Variant
    Dim array2() As Variant
    Dim time() As Variant
    Dim yArray() As Double
    Dim m, i, size, index As Integer
        
    array1 = firstArray
    array2 = secondArray
    time = timeArray
    index = seriesIndex
    
    i = 0
    size = UBound(array1, 1)
    ReDim yArray(size)
    
    For m = LBound(array1, 1) To UBound(array1, 1)
        
        yArray(i) = array2(m, 1) / array1(m, 1)
        i = i + 1
        
    Next m
    
     If ActiveSheet.ChartObjects.Count <> 0 Then
         ActiveSheet.ChartObjects.Select
    End If
    
   With ActiveChart.SeriesCollection(index)
    .XValues = time
    .Value = yArray
       
   End With

    
    
End Function