Check local building codes and permit requirements
Measure the total rise from deck surface to ground
Decide the stair width and location
Calculate the number of steps using a consistent riser height
Determine tread depth and stair angle
Select pressure-treated lumber or approved exterior materials
Cut and install stair stringers
Attach a ledger or support at the deck framing if required
Secure the top of the stringers to the deck structure
Install risers if desired or required
Install treads with proper spacing and fasteners
Add handrails and guardrails where required
Check all steps for level, plumb, and uniform spacing
Secure all connections with exterior-rated hardware
Seal, stain, or paint exposed wood as needed
Inspect the finished stairs for stability and safety