First you need to cut the board sections. You want six 2'X2' sections of medium density fiberboard.
I bought 3 2'X4' panels of MDF. I used a skill saw and a straight edge clamp to make sure the cuts were straight.
I trimmed the long edge down to exactly two feet, then cut the boards in half, measuring 2 feet from one side, and finally trimmed the three panels that were about an inch longer than 2 feet.
Draw out the basic shape of the hills on the board sections, mark where you want hills and cliffs.