• In your hierarchy, navigate to World Constraint (almost at the bottom) > Container > stage.

• In the inspector tab of "stage", under Mesh, click the little circle dot thing and select the Stage mesh from the list.

• Apply the Stage material (found in the MATS folder) in the material slot.

• If you do not wish to see the stage while you're trying to edit things, DO NOT hide anything other than the "stage" thing. Not the container, not the World Constraint. "stage" is what gets toggled by the animation. (Or just use the hierarchy eye hide thing of course)

Also for some reason the medium version doesn't have gogoloco.
Other than that, everything should work as intended!