[Dave Canon]

It depends on your learning style but I would by a good general book on digital photograpy (say by Tom Ang) and work my way throught it expeimenting along the way.
Don't be afraid to try different shutter speeds or different apertures for the same scene so you can later look at the differences and learn for yourself.

I think you would learn a lot from using the manual settings both for exposure and focusing. I do use automatic settings on my camera some of the time but I have 35 years experience so know when I can use automatic and when I need to use manual. You need to build up experience to make these decisions. Of course, meanwhile, if you have some important shots to take and are unsure, then stick to automatic.