Have you every seen a bathy chart? Its not the least bit like the regular charts, more like a topographic map. Other than the lat/lon references there is nothing on it but lines and squiggles. Once you get used to it, you pick out troughs, risges etc. Easiest was to get an idea is to go to a map store and buy a small topographic map. The only difference is that the chart won't have colors, i.e. the greens, browns and blue background colors, all it will have is the lines.
They show the natural depth contours. That's all "structure" really is the rise and fall of the bottom. I haven't seen any wrecks on mine, but I'm not sure there are any wrecks in the areas where I have been fishing.