The wall-framing takeoff already laid out stair flights with guards and a handrail, but a landing's open edges were left unguarded in the order. It now takes landing: {openEdges: ["end", "side"]}. Each open edge gets posts at both ends and past every 72 in, vertical balusters spaced so a 4 in sphere cannot pass (29 in long under a 36 in guard), and a top and bottom rail that join the cutting-stock order. On a 36 in landing edge that is 6 balusters at 3-3/8 in clear.
Limits: corner posts are not shared, so the post count runs slightly high, and all figures are hand-computed, not checked against a built stair. Check your local code book.