Space out your posts evenly along the railing, and screw them together using 1 ½” - 1 ¾” long coated drywall screws. These are narrower than deck screws and have a fine thread.
Next, screw the bottom of your railing to a green treated 2x4 using 2” deck screws, after pre-drilling the holes, and routering the top and bottom if you wish, of the 2x4 to taste. Do the same thing to the top 2x4, called the cap rail, routering that as well.
Next, attach small angle brackets to your new railing and screw them into the posts using 2 ½” deck screws, ideally the cap rail should be right at the place the railing squares out. Go all the way around your new deck, leaving a space open for the steps.
Now, most of the time, you can purchase your steps from Home Depot or wherever you purchased everything else. You will find average sized steps everyone uses. If your height is a little higher, you can form and pour a concrete riser to set the steps on.
This is done with 2x4's or 2x6's nailed or screwed together and concrete poured into it, on a gravel base. I usually poured out a pad underneath this or used natural stone set in place as a landing area and it all turned out very well.
However, there are times when you have a higher than average, or more complex stair arrangement than can be purchased. Now you need custom steps built. This is something far more complex than can be covered here without diagrams, and takes a lot of reading and re-reading to comprehend. This is not a knock on your intelligence; it is just something that takes a lot of time, effort and practice to master.
You're better off hiring someone to do this for you. Just make sure, in keeping with your theme here, that they use screwed in deck boards for steps and risers. Once you stain/seal your deck, you won't be disappointed.
Now for the stair railings, allow yourself some extra lumber in case you mess up. Use the same method as above except you will have to allow for the angle. First, install the railing posts. Use the same method as for the others.
Now, hold your cap rails up where you will have them installed, and mark your angle. Cut them narrowly wide of your mark and set them in place, trim if necessary.
Next, hold your 1” pieces up mark and cut them. Now your bottom pieces the same way, measuring down for your depth.
Next, lay your pieces out on the deck with guides, measure across top and bottom for square and layout your posts. Mark each side for the angle and cut them to fit. Screw it all together and install.
There are math equations to work this out, but the surest way I have found is to trace and cut. Once you get a feel for it, this method rarely fails you. If you want to get used to trace and cut, I suggest a 4'x8'x ¼” piece of plywood cut into strips. Practice it a few times and get the feel for it.
Now sit back, grab a beer or cup of coffee and look out on your accomplishment. You've done a good job and will have a deck to last for many years to come.
