A wall is then crafted around the brackets. Then the concluded treads are bolted in place. These treads could be of steel or wood or wood clad steel. Cantilever steps should be made by a structural engineer, in order that they remain horizontal and rigid with use after some time. https://staircaseinspirations.weebly.com/blog/the-rise-of-cantilever-staircases-in-contemporary-homes