Hi, Debbie. On a "Men in Toolbelts" episode, Ed and Joe installed one. It is more than a one person job but I'm sure that you could do one if you got the proper kit. What you basically do is install a pipe from the ground floor to the second floor then slip the stair segments over the pipe. Next, align the stair segments around the pipe then screw on the tread material and the risers for the handrails. Finally, install the precurved handrail.
This is not a "from scratch" project and I'm sure that the total rise has to be measured very carefully. Almost everything was done with hand tools and an electric drill. Where the kit was produced, they had to have some pretty good metal cutting and welding equipment along with some very good bending equipment for the handrail.
Sorry but I have no idea who the kit manufacturer was. I'm sure that you could do a search on the web and find several manufacturers who could supply this kind of kit.