@Manichean
Yes you're quite right - it's not "the" help page or even "the" tutorial - as you pointed out it's "a" tutorial - my mistake
As dwanthny pointed out I found it through a link from Calibre's help page - hence my confusion.
That being said, it is an excellent introduction to creating TOCs with Calibre - even if it does discourage the use of inline TOCs.
It does also show screen shots (outdated, but still useful), illustrating the specific way to get the thing done. For the purpose of getting started, I find that a few alternative perspectives can be more useful, than sticking to a single approach - that you didn't understand in the first place
I hadn't intended to offer praise or criticism to anyone - my intention was only to point the OP towards something that might help.