this link will show you how to weave the body using peacock herl and yarn
using the link, you will notice that the herl remains on top of the body and the yarn is on the bottom.
http://flyanglersonline.com/flytying/fotw/4198fotw.php
thats the best i can come up with.
it may be a good idea if you have a fly shop in your local area to ask the owner if he or someone who knows how to weave to teach you.
you may also want to GOOGLE "potts weave", "overhand weave" to find more images or website that will show the process. you tube would also be a good source of instruction.