Hi, again, Eden. I have an idea for you. Instead of building stairs, just build a series of boxes. Make the boxes out of 2x8 or 2x10 ripped to the total rise minus the thickness of the decking, divided by the number of steps you want. Make every box smaller by a tread width as you go up. Then you can just lag screw the boxes to cleats inside and put on the decking. You can either make boxes for 2 sides with one set longer and one set smaller so you end up with an L shape or you can make L shaped boxes right off. This way, all you have are straight cross cuts and you don't have to worry about stringers. Make the risers out of pressure treated and you can put on any kind of decking. Dig out the ground about 4 to 8" deep and a foot or so wide where the bottom box sits on the ground and put in gravel. That way you can easily relevel the stairs when you need to. Make sure that all your fasteners are galvanized. Putting in hand rails might be easier for you with this system than working off stringers.