Insert/Delete columns based on a cell value - excel

Question

I have no experience in Visual Basic and I am trying to add or delete columns based on a cell value while keeping the same format from the first column. I´ve seen some posts but my programming knowledge is very basic and I can´t find a way to adjust variables for it to fit into my file.
The following code seems to work for the post I read but as I said I don´t know what to change for it to work in my file:
Option Explicit
Private Sub Worksheet_Change(ByVal Target As Range)
Dim KeyCells As Range, ColNum As Long, TotalCol As Long, LeftFixedCol As Long
Dim Rng As Range, c As Range
Set KeyCells = Range("B1")
If Application.Intersect(KeyCells, Target) Is Nothing Then Exit Sub
If IsNumeric(KeyCells.Value) = False Then Exit Sub
ColNum = KeyCells.Value
If ColNum <= 0 Then Exit Sub
Set Rng = Range(Cells(3, 1), Cells(3, Columns.Count))
Set c = Rng.Find("Total") 'the find is case senseticve, Change "Total" to desired key word to find
If c Is Nothing Then Exit Sub
TotalCol = c.Column
LeftFixedCol = 2 'Column A & B for Company and ID
Dim i As Integer
If TotalCol < LeftFixedCol + ColNum + 1 Then ' Add column
For i = TotalCol To LeftFixedCol + ColNum
Columns(i).Insert Shift:=xlToRight, CopyOrigin:=xlFormatFromLeftOrAbove
Cells(3, i).Value = "Column " & i - LeftFixedCol ' may not use this line
Next i
End If
If TotalCol > LeftFixedCol + ColNum + 1 Then ' Add column
For i = TotalCol - 1 To LeftFixedCol + ColNum + 1 Step -1
Columns(i).Delete
Next i
End If
End Sub
Is it too much to ask if somebody could please help identifying each code line or give me a more simple code to work with?
The following gif shows exactly what I am trying to do:
Thanks beforehand!

Answer 1

A Worksheet Change: Insert or Delete Columns
This code mustn't be copied into a standard module, e.g. Module1 as you did.
It needs to be copied into a sheet module, e.g. Sheet1, Sheet2, Sheet3 (the names not in parentheses), of the worksheet where you want this to be applied. Just double-click on the appropriate worksheet in the Project Explorer window (seen on the top-left of your screenshot), copy the code to the window that opens and exit the Visual Basic Editor.
The code runs automatically as you change the values in the target cell (B1 with this setup) i.e. you don't run anything.
Option Explicit
Private Sub Worksheet_Change(ByVal Target As Range)
On Error GoTo ClearError
' e.g. to prevent
' "Run-time error '1004': Microsoft Excel can't insert new cells because
' it would push non-empty cells off the end of the worksheet.
' These non-empty cells might appear empty but have blank values,
' some formatting, or a formula. Delete enough rows or columns
' to make room for what you want to insert and then try again.",
' which is covered for the header row, as long there is nothing
' to the right of the total column, but not for other rows.
Const TargetCellAddress As String = "B1"
Const TotalFirstCellAddress As String = "D3"
Const TotalColumnTitle As String = "Total" ' case-insensitive
Dim TargetCell As Range
Set TargetCell = Intersect(Me.Range(TargetCellAddress), Target)
If TargetCell Is Nothing Then Exit Sub ' cell not contained in 'Target'
Dim NewTotalIndex As Variant: NewTotalIndex = TargetCell.Value
Dim isValid As Boolean ' referring to an integer greater than 0
If VarType(NewTotalIndex) = vbDouble Then ' is a number
If Int(NewTotalIndex) = NewTotalIndex Then ' is an integer
If NewTotalIndex > 0 Then ' is greater than 0
isValid = True
End If
End If
End If
If Not isValid Then Exit Sub
Dim hrrg As Range ' Header Row Range
Dim ColumnsDifference As Long
With Range(TotalFirstCellAddress)
Set hrrg = .Resize(, Me.Columns.Count - .Column + 1)
If NewTotalIndex > hrrg.Columns.Count Then Exit Sub ' too few columns
ColumnsDifference = .Column - 1
End With
Dim OldTotalIndex As Variant
OldTotalIndex = Application.Match(TotalColumnTitle, hrrg, 0)
If IsError(OldTotalIndex) Then Exit Sub ' total column title not found
Application.EnableEvents = False
Dim hAddress As String
Select Case OldTotalIndex
Case Is > NewTotalIndex ' delete columns
hrrg.Resize(, OldTotalIndex - NewTotalIndex).Offset(, NewTotalIndex _
- ColumnsDifference + 2).EntireColumn.Delete xlShiftToRight
Case Is < NewTotalIndex ' insert columns
With hrrg.Resize(, NewTotalIndex - OldTotalIndex) _
.Offset(, OldTotalIndex - 1)
' The above range becomes useless after inserting too many columns:
hAddress = .Address
.EntireColumn.Insert Shift:=xlToRight, _
CopyOrigin:=xlFormatFromLeftOrAbove
End With
With Me.Range(hAddress)
.Formula = "=""Column""&COLUMN()-" & ColumnsDifference - 1
.Value = .Value
End With
Case Else ' is equal; do nothing
End Select
SafeExit:
If Not Application.EnableEvents Then Application.EnableEvents = True
Exit Sub
ClearError:
Debug.Print "Run-time error '" & Err.Number & "': " & Err.Description
Resume SafeExit
End Sub