Hi! no Batreps yet hehe, the materials were the following:
With the first corner, the beige one, I used cardfoam ( I am not sure of it English name) and textured the outer part with filla or similar (you can use water, fine sand, white glue and plaster of Paris), I used some wooden sticks (those stirring sticks from Starbucks are usable), then beach sand for the base, some rocks, plastic bits etc.
With the higher corner, the grey one, I used the core of a 1/35 model diorama, and then added a floor made of wooden sticks, some filla to fill the gaps and I think thats all, nothing too fancy. The painting time was far more time consuming than the building time.
Cheers!