Attaching steps to your deck brings up the old rule of thumb, measure twice, cut once. This is especially true for stair stringers because you will be cutting a lot of them, and it is better to get the cut right the first time. You will use only basic tools and joist hangers to get this job done, and virtually anyone with do it yourself experience will be able to accomplish this task.
Things You'll Need
Screwgun with Phillips bit
2-inch to 3-inch deck screws or frame hammer and 8-penny galvanized nails
Measure the distance between your two stringers, depending on how wide you want your steps to be. Remember that the steps hang over the edge of the stringers about 2 inches on each side. Also measure the distance from the top of your deck past the bottom of the bandboard (the bandboard is the board that runs around the outer surface of the deck), which will be 12 inches. Place the top of the joist hanger on your bandboard so the bottom of the hanger is at the 12-inch mark. The bottom of the hanger may hang a bit below the bandboard.
Place your joist hanger at the bottom of the bandboard on your deck. Using your pencil, mark around the joist hanger in case it moves while you are attaching it.
Screw or nail the hanger into place. Set your stringers down into the joist hangers. Screw or nail into the top of your stringers at a 45 degree angle, going into your bandboard. Screw or nail through the sides of the hanger into your stringer. You are now ready to cut and place your steps.
Always use caution when using power tools and wear safety glasses.