General rule of thumb, when offering macros in the non-programming forum, especially to self-professed Excel newbies, always include a boilerplate instruction set on how to install/activate them.

Something like:
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How/Where to install the macro:

1. Open up your workbook
2. Get into VB Editor (Press Alt+F11)
3. Insert a new module (Insert > Module)
4. Copy and Paste in your code (given above)
5. Get out of VBA (Press Alt+Q)
6. Save as a macro-enabled workbook

The macro is installed and ready to use. Press Alt-F8 and select it from the macro list.