The printed instructions accompanying each Foldscope kit are very detailed and easy to follow. Even easier is this excellent 14-minute video tutorial for the assembly. I didn't know about the video when I was assembling the Foldscope, and despite carefully following the printed instructions, I still managed to make a few embarrassing mistakes. I am sharing the protocol below with the comments on these mistakes, so others can avoid them. Hopefully, more new users will comment, pinpointing the assembly steps that turned out to be error-prone for them.