Many samples you find on the internet try to demo a certain feature in the context of a larger use-case. I find this often distracting.
The samples here follow the "write the simplest sample to show the feature" philosophy. Maybe you find this more useful.
Simple local login page with cookie-based session.
Google authentication will simple callback logic on an MVC controller.
Sample showing cookie-based session with OpenID Connect-based authentication and automated access token lifetime management.
Some variations of policy- and resource-based authorization
Shows simple protect/unprotect calls and corresponding key container.
Two variations of how to protect a JavaScript application. SPA is pure JS where the token management happens in the front-end, whereas BFF is a combination of UI front-end and back-end token management.
Simple device flow client.