Generate an 'Outline' (headings, indexes, table of contents?)

I’m not sure what the term is in LibreOffice; my efforts to find the idea in the help file wasn’t helpful. Outline is what it’s called in GoogleDocs and that is what I want to have off-line.

I want to generate a list of the heading style, indented according to the level of the heading, on the left of the screen in an already complete document.

This outline is for internal navigation: click on the text in the outline and it goes to the text in the doc.
The outline is always visible on the left (or right) of the screen.

If this isn’t an option in LibreOffice I would appreciate knowing.
If it is possible, the idiot’s guide to how would be a greatly appreciated.

That’s the Navigator, press F5 to toggle it (on or off). You can dock it (by default on the right, I think, or move it around.
EDIT The Navigator will show a listig of all healings in your document if you format the healings as such - assign style Heading 1 etcetera to them, and in Tools - Chapter Numbering, assign then to the outline levels. When you do that, the headings will appear clickable in the Navigator.

Thank you, I can open the Navigator. Nothing I can click on in it shows the ‘outline’ I’m trying to view however. Any idea on how to generate a list of the Headings, or which of the grayed words it would be under?

See edited Answer.

You’ll need version 7.1.x or higher to have it, the lower numbered versions of 7.1 are experimental but it is visible and usable in 7.1.5.2 for sure. See LibreOffice 7.1 Community: Release Notes - The Document Foundation Wiki

Below is image from LO Math Guide odt. The headings on the right are clickable to take you to the heading in the body.