Let's continue:

Now you will have to change the color of your plane to a more sand like one. I leave that up to you.

Next:

Create a sphere and set its radius to 2.5.

Go to the Edit Polygons menu and reverese the normals under the Normals menu.

I hope you got that...

Now: Create a new material (Lambert for ease of use) and set the color attribute to a gradient ramp. Make a light blue to slightly darker blue color.

Set your camera inside the sphere for you shot... and of course remember to put a light inside the sphere!!! ( I used a point light )

Finally render your scene.

This is what I got in about 5 min work.