there are so many good and bad tutorials on the internet to sift through. i've found that it's mostly just a matter of searching until you find the ones that are specific enough for your skill level and what you're trying to do.
the layers palette is arranged so that the layer(s) at the top will appear above the one(s) at the bottom. just click and drag a layer up in the layers palette to bring it to the front of your document.
hope this helps! let us know if you have anymore questions.