Storage Room Addition

I have recently purchased a home in San Diego that has a 4ft x 4ft concrete pad in the rear where the washer and dryer sit, uncovered. I would like to tear out this pad, re-pour a larger one (10x20) and then frame in a nice lanudry room / storage area. This structure would be attached to the house, but without access from the inside.
I have done enough projects around the house, and followed the Black&Decker home repair manuals enough to feel confident that I can do a good job on the framing, roofing, siding, plumbing and electric. I am a little shakey on pouring the concrete slab. I feel like I know 70% of what needs to be done to pour a decent foundation. I like to know 100% how to do a job before I even buyt the supplies. I am anxious to do this project myself. Where do I go to answer the little questions that I have? Is there a book anyone would recommend, or an online resource.
Specifically, I am wondering, would a 6" slab do, or should I pour a footing that stands a few inches above groundline, and then pour a floor inside the footing? How much gravel is necessary underneath the concrete? What is the best way to attach the framing to the concrete given the size of the structure?
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