Excellent work Sae!!! Keep going!
I'm currently working on the challenge It's still in process, and the pictures are ridiculously bad (because I have no camera I had to take a webcam photo of it), but here's what I have so far!
With cardboard from a cardboard box I made a slightly sloping terrain. I covered it with paper and plan to cover it with either coloured sand or just sand which I'll later paint green. After that I'll start building some houses. Not sure which era I want my town to be yet. I'd like to build a cathedral, but I'm not sure if the whole town will be medieval.
Really good use of materials. You might want to reinforce the bottoms of the pieces so they don't curl or warp. I'm excited to see more!