You didn’t describe what you did in such a way that somebody not being able to watch over your shoulder can reproduce it.
Anyway, Format
>Bullets & Numbering
is not the tool for creating an “outline”. It is used to create various lists and these lists will not be collected in any TOC (unless you use advanced techniques to request that).
An “outline” is the set of headings for chapters, sub-chapters, sub-sub-… You must declare these paragraphs as being part of your outline. You do that by “typing” (assigning a paragraph style) your headings with styles in the Heading n family.
There are shortcuts to facilitate the task: with the cursor in the heading paragraph, press Ctrl+1 to 5. Suck marked paragraphs will be listed in sections Headings of the Navigator.
Creating an outline is independent from numbering it because some documents request unnumbered outline. Once your headings have the right paragraph styles, numbering is controlled from a single location Tools
>Chapter Numbering
. There are multiple choices and every level can be configured separately.
Since you seem to be at beginner level with Writer, I recommend you click on the 1-10 lLevel to set the properties globally.