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With the carpet trimmed for the final riser, position it correctly. The 'kick' from the shorter binding should help it fit snugly against the top landing. If the fit is too tight, pull the carpet out and shave an eighth of an inch off the trimmed edge with scissors. Once fit, secure the top edge of the riser with staples, splitting the pile. Then, use a carpet tucker to push any excess or loose fibers tightly into the gap between the riser and the wall, ensuring a clean, finished look. If any edges appear like they might fray, apply a small amount of hot melt glue to seal them. Finally, secure the runner to the top landing with additional staples, again ensuring the pile is split to conceal the staples. For angled cuts at the side, staple those edges firmly and tuck them in with the stair tool as well.