Django + HTMX - create/update parent model with child models at once

I found a great tutorial about dynamically saving models in django using HTMX:

Video: https://www.youtube.com/watch?v=KVq_DjIfnBo Text version: https://justdjango.com/blog/dynamic-forms-in-django-htmx

My problem is that I want to create author, add books and save author with books at once - using HTMX on one page.

Could you please explain, how to do it? Thank you