The background is fairly simple. Draw a large rectangle over the artboard in "teal" using the Rectangle Tool. With the Pen Tool, draw long shapes radiating outwards from the center (or so) of the design. Unite them in the Pathfinder panel and apply a Radial gradient to the Compound Shape going from light blue in the center and teal at the edges. Most of your design will cover the more opaque portions of the shape in the center..