How to display related model objects in Django in the admin panel?

Question

Django

Good afternoon, I'm learning Django, there is an example of a project - I want to repeat the solution, namely:
There are several models with objects related to each other:
- Series
- Seasons
- Series
- Files for a series

How to display in the administrative panel:
1. The number of related objects with a link to the admin section with a list of related objects.
2. How to add a link to add an object as in the example (green cross in the line)