STEP ONE: The world

We need to define our world. 
PART ONE - What is Ring World? Write a generic article of 500 words or less on this question using the following as guidelines:  How and why are the rings that orbit the planet the location of the races to live on? Why don't they live on the planet?  How do the rings have an atmosphere? 
PART TWO - How does magic work? Write a generic article of 500 words or less on this question using the following as guidelines: How does Magic work?  Does everyone have access to magic?  Is there a difference between arcane magic, divine granted powers, and natural abilities and powers?