table of contents+howto

Go to the rules of any card and click on "table of contents". Click the radio button for the set you want to add or change the table of contents setting for, and enter the minimum number of headers you want to have turn on the table of contents (e.g., if you make it 3, then cards in that set with three or more headers will show a table of contents).

If you set it to 0 (zero), then no table of contents will be generated regardless of how many headers are in the card.