Take your sheet of styrofoam, and cut it about 1/2 cm bigger than the width of your tank. If you want a big land area, just adjust the size of your styrofoam. Don't be worried about weight as with all the rocks it will seem quite heavy. A foot in diameter square of styrofoam will hold 50 pounds! Now peel off all labels on the styrofoam. Make sure the sticky coating isn't left behind. When cutting your styrofoam, be careful not to bend blade, or it will cut messily. Face the uncut edge of the sheet out toward where your turtles are.