anyhow... look at the picture below
so... a triangular prism, is just 2 triangles and 3 rectangles stacked up to each other at the edges, that's all they mean by the "net" bit
so.. get the area of each triangle, and each rectangle, and sum them up, that's the area of the triangular prism
you pretty much have all values, notice, the triangles have a height of 3 and a base of 4