Iain:

It is possible to accomplish the same thing by right-clicking in that
cell and selecting "Paste Special..." from the context menu, but the
documented procedure does work (for me), and I feel that
right-clicking is more error-prone, since your pointer must be placed
correctly when you click, and it may be less obvious if you "miss".

I'm not really sure where Tony was going wrong. It may or may not help
to replace steps 2a, 2b in the instructions with something like:

...
* Ensure that the spreadsheet is scrolled all the way to the top,
such that the row for the first entity ("1A0" or similar) is visible
* Select the "DAY" cell within that row, by left-clicking it (it
should become highlighted with a heavier border). In the 2021
template, this is cell D17, but it may vary from year to year.
* From the "Edit" menu (in the menu bar at the top of the window),
select "Paste Special..."
...

Tony, would you be willing to go through the procedure again, and see
if the above helps?

73,

~iain / N6ML