I want to build 3 steps leading up to an elevated paved landing (yet to be built). I am using sandtone look pavers for the job. Some people say I should concrete first then pavers on top. Other people say just put sand down and tap them down with a rubber hammer. Will sand be enough? If I have to concrete do you just concrete the horizontal flat steps or the vertical edges too? Its in the backyard so limited traffic but only want to do it once.