The manufacturer recommends placing the shed on a flat structure such as a wooden foundation made of treated 2 x 4s and OSB board that you can pick up from your local home improvement store. The instructions show just how to build it and what materials are needed. The other recommendation is a concrete slab. The concrete slab is more pricey to erect. It is very important to make sure it is flat and drains well. If it isn't flat you may run into issues with your doors closing properly. Feel free to contact us with any other questions. Theoretically you could just place it on a level surface, but eroding ground, inability to drain, and problems with the doors might cause problems.