How do I prevent Word from continuing numbering of subheadings from a previous multilevel list?

The example document you linked to, in your very first message in this thread, does make use of the built-in headings. In my previous reply, I was referring to the setup in that example, where Heading 1 is not part of the multilevel list, while Heading 2 and Heading 3 are.

But it doesn't matter which styles you use (built-in or custom ones), as long as you set them up properly so that they are associated with levels in a multilevel list. The rule is that one numbering level must correspond to one paragraph style (and levels can be left un-numbered whenever appropriate).

You do not have your top level (cats and dogs) included in your multi-level list. This is necessary even if they do not have any numbers at that level, if you want the numbering for lower levels  to restart automatically.

I agree with Stefan. The absolute best way to create and use multilevel numbering in Word is to link it to styles as set forth in How to create numbered headings or outline numbering in Ribbon Versions of Word by Shauna Kelly. Doing anything else is asking for trouble.

Once you have this numbering set up, use the styles to change the numbering level, not the buttons on the ribbon or right-clicks.

You will have to make Heading 1 the top level in your multilevel list. This is required for it to restart the numbering of lower levels. You can include Heading 1 and still specify that it should be un-numbered.

Your example document has Heading 2 linked to level 1, Heading 3 linked to level level 2, etc., so you would have to change all the associated styles for your list (via the Multilevel List dialog box).

Hi Stefan- I am assuming when you mention  Heading 1 and Heading 2 (etc.) you are NOT referring to my labels " Main Heading 1" and "Main Heading 2" but to the various indented subheadings below Main Heading 1?

To make it clearer (for me) I've applied the following 'cat and dog' labels so I know what you are referring to (see screen shot below and Outline doc.docx)

Now I don't know whether I am missing something (I probably am!)  but it seems to me the styles are set correctly: I have the label "Cats" set to Heading 1, "Pros of owning cats to Heading 2" and "Cheap to Keep at Heading 3. As you can see from the screenshot, the cursor is resting on "The Pros of Owning cats" and the highlighted style on the right shows Heading 2. And still the next main heading down (Dogs) has its first subheading 'pros of owning dogs' continue the numbering from the previous list (Cats etc) . Appreciate your help!