How does the ToC plugin work?

The table of contents is automatically generated for each post.

By default only the H2 titles are shown. If required you can enable to show H3 headings as well. 

You can also control table of contents to be hidden throughout your blog or per-post basis.

If you want to disable the ToC on any post, you can do so from the "Advanced Options" of each post. You can also control this setting globally via "Settings > Expert"