The written instructions aren't the greatest, so I highly suggest looking at you tube channel Tech Angel.. She has a great assembly instruction video. Once I watched her video, I understood the assembly. The wheel rolls quietly.. Moreso than I expected. I have one cat that has taken to it immediately, and one cat being cautious. It's a beautifully made product.. My main complaint, is some of the screws, the heads aren't made well and some strip too easily. I had to use pliers to loosen those up and replace with a fresh screw. Fortunately, we are given extra screws.. Very thoughtful. The four star is because of the less than stellar screw quality.