I've made a couple so far, and it's becoming easier each time, but as you can see I've made a bunch of mistakes in the process. The most important thing is to have a good sharp knife and a solid surface to work on. It wasn't convenient either that my printer ink just ran out and the template wasn't visible all the way.
Cut out the round template shape and then fold it on the lines on the template, folding it into accordion shape and leaving the gray shades on top, so that you can see where you will have to cut. (There are better instructions on the web if you search for it ;-p)
Once everything is cut out, be veery careful taking it apart. It is very fragile.
Next I will try the storm trooper.