Challenge 2: A Workbook_Open Handler — Solution Walkthrough

Private Sub Workbook_Open()
    Worksheets("Dashboard").Activate
    MsgBox "Dashboard refreshed and ready"
End Sub

Which module this must be placed in:

This code must be placed inside the ThisWorkbook module specifically
— the special object module listed in the VBA Editor's Project pane
representing the workbook itself, distinct from any regular Module
(Module1, Module2, etc.) or any individual worksheet's own module.

Why placing it in a regular module would not work:

Workbook_Open only carries its special "run automatically when the
file opens" meaning when VBA finds it inside the ThisWorkbook
module's own built-in event framework — that's the one specific
place Excel actually checks for a procedure with that exact name at
the moment a workbook finishes opening. A Sub named Workbook_Open
placed inside an ordinary Module is, as far as VBA is concerned, just
a completely normal, manually-triggered Sub procedure like any
written in Chapter 7 — it would sit in the Developer > Macros list
under that name, callable by hand, but Excel would never call it on
its own just because the file opened. The special automatic-execution
behavior comes specifically from WHERE the code lives, not from the
procedure's name alone.

Notes:
- This is the same underlying idea behind Worksheet_Change needing to
  live inside a specific WORKSHEET's own module rather than a regular
  one — VBA's event-handling mechanism is tied to particular,
  purpose-built modules, not to any module a name happens to be typed
  into.