I just got done with one about a month ago. Pretty straight forward. Just follow the directions. It also includes pictures so you can get an idea of how it's suppose to look as you go. I got the majestic 8×12 at HD when it was on sale. Take time on leveling your base and making sure the floor is square. After that it's a snap. It took me 4 afternoons (probably 20 hours) to get the stucture built. With 2 people you can get it done in a full day of work. The finishing took me another 6 hours or so. All basic tools as well. A passload or a nail gun would make it a breeze though.
You have to buy your subfloor separate. 3 sheets of OSB (make sure you don't get tongue and groove, you'll be an inch short) and then roofing supplies and hardware. It does come with a good bit of screws. But I bought deck screws instead.