excel - Workbook_Open sub won't run when I open the workbook?

Question

This program is supposed to create a button that the user can press to activate a different sub. From my searches online, it seems that the sub below should activate when opening up the workbook, but it's not?

What am I doing wrong?

Option Explicit
Private Sub Workbook_Open()
Dim btn As Button
Dim rng As Range
With Worksheets("Sheet1")
    Set rng = .Range("B2:C2")
        Set btn = .Buttons.Add(rng.Left, rng.Top, rng.Width, rng.Height)
    With btn
        .Caption = "To begin the program, please click this button"
        .AutoSize = True
        .OnAction = "TableCreation1"
    End With
End With
End Sub

Answer 1

Make sure your Private Sub Workbook_Open() subroutine is pasted inside of the This Workbook object and not in a Module, Form, or Sheet object.