How is the correct way to create the outlines of a PDF

[abdulbadii]

How is the best and correct way to create the outlines, which Adobe Acrobat call it "bookmarks", i.e. a list/collection of internal links accessed from a separate place/pane provided by the PDF reader, separated from the whole main existing PDF document

Which must be worked based either on:

• The collection of hyperlinks (internal links) as TOC in the existing PDF document
• Not having to do with the PDF doc., but rather the collection of HTML element
  • ...... from which the a PDF is about to be created (by any tool eg. headless browser)

  Please help shed a light as it's been more than two weeks try and (re)search to solve, mostly asking chatbot help, to no avail