Keter Factor Shed 8x11 Assembly

We have been busy working on this project over the last week, including two weekends.
Since we're novice in d-i-y, this whole thing took us around 18 hours from the ground up.
The first part was excavating the lawn so there's a nice even surface (sort of), then it was filled with sand to help with the levelling.
Treated timbers were used to form the foundation for the shed. All these took around 10 hours over 4 days.
Then comes the shed, since we bought it, it should be easy right?
Boy were we wrong, it started easy, but as soon as the walls were up and everything was overhead - neck pain, shoulder pain, everywhere pain! Not only that, many of the holes were not really aligned, and so we had to drill new holes... in the end, us noobs took around 8 hours to complete the shed assembly.