You can turn on the numbers in Pepakura viewer. When you open the file in viewer, look for a box on to that has a little '123' written on it and when you scroll over it it says 'edge ID'. Click it to turn the numbers on.
I also suggest Hugh Holder's files, there in the 3d section. I havent made his helmet, but his other stuff I've made is really high quality and easy to assemble. Also, make sure to use 110lbs cardstock (or at least 65lbs) and either hot glue or superglue, tape is a no.
Hope this helps