Understanding the PlotSquaredAPI

So, I am having a bit of a struggle here. I have been reading the PlotSquaredAPI for about two hours now, and I cannot seem to find what I am looking for with any sort of speed. There doesn't seem to be any help whatsoever on the topics I am looking for online. Is there something I am missing? Like it is ridiculous to search for a half hour to find the method I need. If you know of any resource I have overlooked please let me know.

For example, right now I am trying to figure out how to get the plot area up to the ground level. I have figured out how to get the plot location the player is in with getPlot(playerlocation) and the plot area with getMain().getPlotArea(world, id) but this does not help. My plan is to use the WorldEditAPI and create a selection from there, but first i need to get the cuboid from PlotSquared. But as of now it just returns null, so I believe I have the wrong method, and am unable to find others.