I have been working with Scrum for a long time. I love it for its simple power and its awesome challenges. Before I would ever attempt to explain any of those ideas, I would always start with the most basic idea; what is a scrum team?
After many years, I finally understood that these roles can be explained very succinctly, defined in a way that anyone can understand instantly.
There are only three roles in Scrum and none of them are in charge of the others:
Product Owner: Responsible for the WHAT, WHY, WHO and some of the WHEN
Delivery Team Member: Responsible for the HOW and the rest of the WHEN
Scrum Master: Responsible for the HOW WELL
As with all powerful things, I find that this most basic definition helps people understand the purpose of each of the roles and how they relate, not only to each other, but to the customer and the entire organization around the team.
As to the remaining questions of what does a Scrum Team do and how do they do it, I would simply say:
They are a team of peers. They are partners who collaborate to craft what is most valuable to their customers.
Could it really be any more complex that this? I think not. I have never found anything they do outside of these responsibilities or any purpose beyond what is stated here.