How do I start developing a Twitch Extension?

I’m new to Twitch Extensions and have read the documentation, but I still have some questions about getting started. Can anyone provide a basic overview or additional resources to help me begin developing my first extension?

A Twitch Extension is just a website.
Where that website lives in an iframe on a Twitch channel page

That website requires the inclusion of a Javascript file from Twitch, and you need to invoke the Twitch Extension Javascript Class/helper in your own Javascript, basically as an equivalent to document ready/finished loading.

Everything else is just a website and acts in the same way.

Where the website is hosted in a sub folder on the Twitch extensions sub domain from a dumb/static Nginx assets server (no server side rendering)

That website essentially cannot navigate to new URL’s.

But otherwise its literally just a website.

So to start you need to know how to build a website.

Do you have any specific questions?