"Yeah, thanks.  Just a few questions left, like why doesn't the volumetric cloud I chose show up at all in the render?"

After you insert a volumetric cloud, you have to position it in the scene. If it isn't showing up then it must be below your terrain or hidden by the ground plane. Click on the modeling room icon to adjust your volumetric cloud parameters.

"And how do you get the ground to look like water instead of that flat... whatever it is?  And I've already looked in the manual, it just goes on about water spouts and other weird stuff, nothing simple - help?"

I think you said you turned off the ground in the realistic skies. If not then do that.  Insert an infinite plane into the scene and drag one of the preset water shaders onto it.

"Also, please, please, please, how do I save textures/shaders/materials that I've jiggered with to create something I like better than the basic stuff already in the wizard?

I just can't figure out how to save it - help???"

Select the object whose shader you want to save. Click on the shaders tab in the bottom right tray. Click and drag that shader from the right tray into the bottom browser tray. Make sure you have the shader tab and  whichever folder you want to save it into opened up.