Taxonomies and WordPress Post Types. How to generate page addresses?

Question

Taxonomy

I ask the WordPress gurus for help. Completely confused with taxonomies and records.
What you need, using the news catalog as an example:
/news/ - directory address (archive), list of all news
/news/animals/ - category, list of news about animals
/news/animals/koshka_rodila_kotenka.html - news page (exactly from .html to end)
/news/add.html - page for adding news
At the moment, taxonomy has been added (news_categories, news categories), post type (news), a couple of keyboards are broken)) and returned to the original:
/news/ - everything is super
/news_categories/animals / instead of /news/animals/
/news/koshka_rodila_kotenka instead of /news/animals/koshka_rodila_kotenka.html
/news/add.html - it's not at all clear yet how to implement, add an endpoint or something else, the main thing is that you can connect a file or display the page content with a function
. I'll be glad for any hints in which direction to move.