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Install a 4x4 post at the bottom of the stairs to support the handrail. Since the stairs are on a concrete pad, a metal post anchor (or bracket) is used. First, position the anchor, mark the hole locations, and drill into the concrete using a hammer drill with a masonry bit. Clean the holes, insert hammer-drive anchors, and secure the metal bracket. Then, fit the 4x4 post into the bracket and secure it using screws. Check the post for plumbness with a level. To install the top handrail, determine the required height (typically 34-38 inches from the tread nose). Cut the top of the post to this height, considering the thickness of the top rail (e.g., a 2x4). Mark the angle for the top and bottom rails by holding a scrap piece against the post and steps, tracing the angles. Cut the top and bottom rails to length and angle using a miter saw.