Based on the script from Pete R. Jump To (peachananr) and integrated by us in Drupal 8. The module displays for wider screens a menu to navigate within a text. (Swiping is easier for small screens)
You can use two levels ...
How does it work?
1) You set the textfield that you want to use. This should make it possible to use it in other contenttypes and other text fields.
2) After that you set the header, you want to see in the menu (here h2). All Headers of this type now automatically come in the menu. The lower level (here h3) will also be included as a submenu. You should of course make that you use the appropriate headers in the text field.
We choose h2.
3) Finally, you can also select the menu background color.
For the background color, there is a color field.
The menu can also be folded up.
1) Install the dependencies
2) Install the module
3) Go to the new content type and add content