Auto populate column based on drop list, auto populate other columns

I am still a newbie trying to fly when I can hardly even crawl yet.

This code on it's own works fine to populate Master SHEET Columns D,E,F,G based on what is pasted into Master SHEET Column B.

Ref: CODE A

Option Explicit

Private Sub Worksheet_Change(ByVal Target As Range)
Dim RNG As Range

    Application.EnableEvents = False
    On Error Resume Next
    Set RNG = Range("B:B").SpecialCells(xlConstants)
    If Not RNG Is Nothing Then
        RNG.Offset(1, 2).FormulaR1C1 = "=""Deny from "" & RC[-2]"
        RNG.Offset(1, 3).FormulaR1C1 = "=""Allow from "" & RC[-3]"
        RNG.Offset(1, 4).FormulaR1C1 = "=""/sbin/iptables -A INPUT -p udp -s "" & RC[-4]& "" -j DROP"""
        RNG.Offset(1, 5).FormulaR1C1 = "=""/sbin/iptables -A INPUT -p tcp -s "" & RC[-5]& "" -j DROP"""
    Else
        ActiveSheet.UsedRange.Offset(1).Clear
    End If
    Application.EnableEvents = True
    
End Sub

This code on it's own partially works in that a selection from the drop list will get data just not the correct data, it gets all data.

Ref: CODE B

Option Explicit
Private Sub Worksheet_Change(ByVal Target As Range)
    Dim LR As Long
    LR = Sheets("Data").Cells.Find("*", Cells(Rows.Count, Columns.Count), SearchOrder:=xlByColumns, _
                           SearchDirection:=xlPrevious).Row

    Application.ScreenUpdating = False
    Application.EnableEvents = False

    Sheets("Master").UsedRange.Offset(2, 0).ClearContents

    With Sheets("Data")
        .AutoFilterMode = False
        .Range("A2:AA" & LR).AutoFilter Field:=1, Criteria1:= _
                                       Sheets("Master").Range("A1").Value

        .UsedRange.Offset(1, 0).SpecialCells(xlVisible).Copy
        Sheets("Master").Range("B2").PasteSpecial
        .AutoFilterMode = False
    End With
    
    Application.CutCopyMode = False
    Application.EnableEvents = True
    Application.ScreenUpdating = True

End Sub

What should it do?

The drop list should have a blank line when selected this clears the sheet below Row 1 so as to preserve headers.

When you select from the drop list the macro should find the column of data related to that selection
and automatically populate Master SHEET Column B (CIDR).

With Master SHEET Column B (CIDR) populated trigger the population of Columns D,E,F,G

Example:
If AF - AFGHANISTAN is selected this should only get Column A from SHEET Data and populate Master SHEET Column B (CIDR).

The now populated Master SHEET Column B (CIDR) should trigger Ref: CODE A which should now populate Master SHEET Columns D,E,F,G

Attached workbook is using Ref: CODE B as a filter function in module 1 manually run for now so as to not interfere with macro in Master SHEET