Instructions
Enter "Create Mode" and press the "Square" button to open the Popit menu.
Select "Tools Bag" and press "X" to open it.
Select "Change Material" and choose what you want to change the ground to. Options include glass, rubber, metal, cardboard and several others.
Select the ground or platform you want to change to your selected material and press "X." You can do this multiple times to change different objects.
Press the "Circle" button to return to the Popit menu.