An open box I guess: You can build it with the default 3d shapes of sketchyphysics (boxes), one box for the base, and four boxes more for the walls. Then in UI all of them should be checked STATIC, and even the base STATICMESH too, just in case.
Then for the can, use the default cylinder, and whe right-clicking on it: sketchyphysics >> shape >> cylinder. Then multi-copy that can.
Press the play, when it's done you can save the model in skp and changes will be saved.
If you already had built all the objects before, you can edit each group, and "introduce" inside of them the objects I explained above, and then hide them. SKetchyphysics will still recognise them.