How would I finish this as a solid?

How would I finish this as a solid or am I approaching this the wrong way? Dimensions defined in the representation are representative of the curvature of the land where I will be placing a chicken coop. The exercise I am attempting is the layout of 8x8x16 block to make the surface even. I want to determine the number of blocks needed to construct it. Hope that makes sense.

The image shows a shape with no bottom. As such, it cannot be a SketchUp solid - it does not enclose a volume. You need to add a bottom. It appears that the edges are not coplanar, so the bottom surface will need to split by drawing diagonals across it.