Hi , how to install a shed in my backyard ? It seems very complicated .

Hello. Then you can find out how to install a shed here in your backyard on this blog https://ultraassembly.com/blog/assembly-and-installation-of-a-wooden-storage-shed/ . It is quite useful and describes the important points in great detail and also points out those that are worth doing with special care, but there is also a lot of information about small construction and furniture here in general.