How to make a 3-level site structure in Worpdress from custom posts?

Question

WordPress

There are three types of posts:

• Parts of the world
  
• Countries
  
• Cities
  

Each post has its own template.
How to implement, so that the url is, for example, domen.ru/asia/china/pekin/ It is
necessary that, when you select a parent post, the url is generated automatically.
https://1fix.io/blog/2016/02/05/parent-from-anothe... - found a semi-working example. There is a 2 level structure here.
I tried to find freelancers, but there is only spam.