Your screen shot indicates a clear hierarchy, with different indents. I would recommend using multiple paragraph styles for this.
If one level is always supposed to be auto-numbered, you can set the whole thing up as a multilevel list (to control numbering restarts) but only one level should have actual numbering applied to it of course. The general principles are discussed in the article at
https://shaunakelly.com/word/numberi...g20072010.html.