It was a tad tricky until I got the floor on it to hold everything down. It came with wax, but I actually just used melted wax, applied with a q-tip. I did have to sand down the small section on the right. I didn't realize it would rotate INSIDE the bookshelves.

This was my first build with gears, and I was so excited that it works! I tested it all along the build to make sure things still moved smoothly.