Numbering which doesn’t need to be under a ‘heading’

I have read numerous posts on numbering, headings, contents pages however I want to do the following;

First level – Heading 1 – with a number and go to contents page
Second level – Heading 2 – no number and go to contents page
Third level – ?????? – number 1.1, 1.2, 1.3 etc and not go to content page

At the moment I have the level 1 and 2 headings working well

If I put level 3 into ‘headings’ then it goes to the contents page and I cannot work out how to have level 3 which automatically updates numbering as I type

Any help appreciated