Thanks again for all your help. I am missing a lot of the shorthand here, which makes it tough to figure out what goes where. How do I associate the code with the arrow element? Place it where?
Unfortunately, the tweaked document that you provided does not work.
Based on my experience with other languages, you drop in some code that loads with the document, you apply a tag a specific target, then you attach a script to the trigger object that points at that tagged object. Clicking on a button to insert HTML is straightforward, as is assigning an ID to the target. Attaching the trigger script is confusing me. This gets more complex with relative layouts.
By 'Unique Element ID' I mean this field in the Identity Inspector:
That was built by taking advantage of a JavaScript tool called 'Tocify' which takes headers in regular HTML and generates a table of contents for you and creates links. Some more info on that in this post.