Yeah, that's about it. If you're entirely new to PS, I'm sure you'll find the layer feature effective. Using layers for the previous example, the shoe could be in one layer, and the background could be in the other. That way, the shoe layer can be "moved around" to any location and still stay on top of the background (or the "bottom layer"). It's easier to edit layers as well, as you can paint one layer in color without risking to paint over another layer which you want to stay intact.
You might also find the 3DBuzz Photoshop video training modules useful. You can find them here:
"Stephen Wolfram is the creator of Mathematica and is widely regarded as the most important innovator in scientific and technical computing today." - Stephen Wolfram