New Content: Links to more basic Matter and Thread tutorial content

[cecille]

Why is this content needed
The how it works section has great technical detail, but seems to jump in very fast. New developers could really use a more gentle introduction.

Who will benifit,
New developers, casual readers just looking to understand more

Are you able and willing to create the content
I think some of this is already available, we just need to link in. We have some available internally that we could polish up and donate. No guarantee on timeline, just adding a note here for tracking