Create sidebar navigation with dropdowns that persist

I’m trying to create a tutorial, wiki-style website with a left-hand-side drop-down navigation with multiple drop-downs that stay open as users read different articles.

The navigation should act something like this website or this website.

I haven’t been able to find any tutorials helping me with this:

  1. How do I have the drop-downs stay open when a user clicks on a specific article?
  2. How do I have the selected drop-downs be open automatically when someone goes to a specific URL but doesn’t navigate throughout the website to get there?

Any tips, links, or guides would be extremely helpful!


Here is my public share link: [LINK]