Here is my how to on making a desert diorama. Its my first diorama so if you think it turned out bad then is a what not to do.
Green "Grass" flock
I started out but getting my piece of styrofoam
I took a figure and laid him down so I could make the length about long enough to lay him down on it. Leave extra room because you will cut the board down.
Cut off where you want it. Then break up the square shape but cutting curves using the exacto knife.