When I got my D80, I didnt even use the auto.. I wouldnt let myself have all this control of my equipment, and let the camera decide... The main things to learn first off are the effects / results you will get from shutter speed and aperture. Just find a subject and shoot it at different aperture and shutter speed settings, and look at the images so you can tell how much difference each click makes. Once you start understanding that, youll start feeling more comfortable with your equipment, and eventually move on to learning other, more complex things.
Remember.. shutter speed - the longer your speed is set the longer the shutter stays open allowing light to come in to expose the image... ( If you let too much light in the image will be to bright.. If its darker outside or where your shooting you should shoot at lower shutter speeds. And the brighter you can shoot faster.
Aperture is how " big " the "eye" is open. Remember the SMALLER the number the BIGGER the openening ( like gauges ). Again if youre pictures are too bright.. Try closing the aperture some.. or vise versa... Think if it like an eye... If you look at the sun with your eyes wide open its gonna be bright and not pleasant... If you squint your eyes more closes.. Less light will get in and it wont be as bright and unpleasant.
I hope this makes as much sense to you as it does to me