A sandbox is the scene or environment that is created within the Sandbox AR app.

When using Sandbox, there is the option to use a pre-created sandbox or to create your own environment from scratch.

To create a new sandbox, select Create New from the main library screen.

Next, select a stage by scanning a flat surface (eg, a table top or floor.) Some surfaces are harder to discern than others, so it may be a good idea to move around your area until you find a suitable surface.
Tap Add Stage.  
Then, select the type of surface design you would like to use, such as grass, sand, snow or concrete.  You can tap each one to see what it looks like.
Move your device (or yourself!) to position the stage and then tap Place.

Finally choose a background for your scene.  You can choose from a green or blue screen (to add effects at a later date), a space background, a sunset or even an underwater background.
Tap Background on the left-hand menu to cycle through the options.

If you would rather that the scene appears in your real environment, select Camera for the background.

Clearing your Stage
If you need to clear your work and start again, open the main menu and tap Clear Stage.