the ramp on a toy so that it is less steep. if you want to put the wheel on one of the shelf levels then i recommend deciding this first as it determine where your shelves need to be positioned.
i recommend filling the bottom level with bedding and larger toys before attaching the cage to the base as it would be hard to get them in otherwise. the middle area i would recommend for smaller toys as getting larger ones through the door is tricky! the top area is great for hanging toys and is easily filled with large toys due to the large top door.
the cage can be lifted 