Sub-chapter 1
This is a deeply nested sub-chapter. Take a look at the Org source. It requires that you create several headings and create the index in a sub-heading of the same name. It is a strangeness about ox-hugo that this is required. If you make a strictly hierarchical outline, the content will be duplicated, however the structure we’re using hides the nested content on the index pages, leaving it for the nested page only.