My advice... Don't do-it-all-yourself. Novice and pro alike can benefit from each other in DIY. You might have the shed location leveled by a landscaper; get a referral to outsource the shed's foundation to a building subcontractor; you can even have the roof's trusses made by a local truss company and the shingles installed by a handyman or roofer.
Assemble the four wall structures. Wall structures are usually nailed to the underlying support from the bottom up. However, if this is not possible with the design you’ve chosen, simply nail them downwards through the plywood and joists or toenail them into place by driving the nails downwards and at an angle. Note that you will probably need other people to help you hold the wall structures up until they can be attached to one another.
Once you’ve received the package and all it entails, you can begin creating your own outdoor shed whenever you feel ready. The only time you need to exert the effort is when you’ve begun construction. When you do decide to start, make sure that you have a decent amount of time as well as motivation to carry through the whole project. You don’t want to be left with an unfinished shed out in the yard, a constant reminder that you tried and failed.
I got suckered into the 12k shed plans, only to find myself falling for one of the oldest scammer sales pitches in the book by being up-sold into the add-ons. Before I clicked I did a quick review and the first few sites that popped up had said that it was worth the money to buy the add-on because that is where the real value was (perhaps a review page planted by the good folks of MyShedPlans).
Before a hammer hits a nail: plan, plan, and plan some more. All too often people visit local home centers to get shed ideas. They go inside the prebuilt sheds in the parking lot and decide their own storage needs right then and there. Even worse, they'll grab a few brochures and use those ideas to find a shed design online without doing any proper space planning.
Nail plywood sheeting to the joists to form the floor. If necessary, use H-clips in addition to nailing the sheets into place; these fit between two pieces of plywood and lock them together for additional structural strength. In the example design, two standard sheets of 4- by 8-foot plywood are used whole and a third is sawn in half and used to fill in the 4-foot difference on either end. Because of the spacing of the piers, support beams, and joists, no additional cuts or adjustments are necessary. Note that the pieces of plywood are intentionally misaligned so that the floor doesn’t have a single seam running across the whole thing, which would be a significant structural weakness.
Build the framework for all four walls. To account for the fact that the front and back walls are different from each other (due to the doorframe in the front) and the side walls must both be sloped (to prevent rain from collecting on the roof), each of these will have to be tackled somewhat differently. It’s easiest to construct the back first, the front second, and the two sides last, as shown in the numbered image below. See How to Frame a Wall for more information before you read the instructions below.