The first way is simple just add an extra ring to the edge. This gives two rings on the edge that gives it a hemmed look. This is good for edges like around the face in a coif.
The second way is to use the box chain for the edge. This is easier than it sounds the time consuming part is making a box chain long enough for the edge.
To attach the box chain to the chain mail is easy.
To attach the box chain to the chain mail lift up two rings from the one side of the box chain and attach one ring. Then you can splice the two together.
I hope that you enjoyed this as much as I did in putting it together. I will be more that happy to answer any questions you have about chain mail. If you have a problem fill free to e-mail me and I will try to help you work out a solution.