New Workbook and Assign References

[ChaosPup]

Hi everyone, I'm working on a project just now that I'm using to create a number of new worksheets named and populated from user entered data on a different sheet. I've got it working great so far with this -

Sub COPYFAT()

Application.DisplayAlerts = False   'Turns OFF error reporting overwrites file without prompting
Application.ScreenUpdating = False
   
   'Varible declarations
   
    Dim UnitNum As Variant      'Number of units
    Dim SheetName As Variant    'Name of sheet
    Dim I As Integer            'Counter
    Dim Start As Integer        'First SN
    Dim Increment As Integer    'SN+1
    Dim xNumber As Integer
    Dim xName As String
    Dim xActiveSheet As Worksheet
    
    Start = Sheets("Control").Range("B10")
    UnitNum = Sheets("Control").Range("B9").Value - 1         'Number of units pulled from CELL B23 on control sheet ***-1 because index starts at ZERO***
    Worksheets(Range("B8").Value).Activate                    'Name of Sheet to copy from CELL B8 on control sheet
    Set xActiveSheet = ActiveSheet
            
    For I = 0 To UnitNum                                      'Planning to add this number to cell reference for name starts at zero so initial reference is correct
        Increment = Start + I
        xName = ActiveSheet.Name
        xActiveSheet.Copy After:=ActiveWorkbook.Sheets(xName)
        ActiveSheet.Name = Sheets("Control").Range("B12") & "-" & Increment
        ActiveSheet.Range("A1") = Sheets("Control").Range("B12") & " Factory Acceptance Test Report"
        ActiveSheet.Range("I4") = Sheets("Control").Range("B8") & "-" & Increment
        ActiveSheet.Range("I2") = Sheets("Control").Range("B12")
        ActiveSheet.Range("I5") = Sheets("Control").Range("B13")
        ActiveSheet.Range("I6") = Sheets("Control").Range("B14")
        ActiveSheet.Range("I7") = Sheets("Control").Range("B15")
        ActiveSheet.Range("K10") = Sheets("Control").Range("B17")
    Next
    xActiveSheet.Activate
    
Application.DisplayAlerts = True                              'Turns ON error reporting
Application.ScreenUpdating = True

End Sub

There are 2 more things I'd like it to do - instead of creating the new sheets in the current workbook containing the template, I'd prefer it to create them in a new workbook that is then named and saved. I've implemented this in a different project creating word documents, but for some reason I'm struggling to do it here. The other things is, each sheet is named after a serial number, and each serial number has a corresponding reference number (which are client supplied and be any mix of numbers, letters and symbols). I'd like to list the reference numbers in the order they are fitted to serial numbers (which I'll copy/paste from a another sheet I'm given), then have the macro populate each sheet with the relevant reference number. I'm not sure where to start with this one! Any advice would be most welcome. Thanks!