Template:
http://3.bp.blogspot.com/-rCvMpkVBP9Y/T8YrxhIgybI/AAAAAAAAGYU/BStLcMYf8dg/s1600/peter.png
not mine.
1
Draw your own template o print one from the web.
2
Cut it.
3
Cut the leather in the shape of the template.
4
Repeat, you need two!
5
Sew the two halves with the needle. Only a little!
6
Add the button..
7
Add the jump ring on one extremity..
8
The chain...
9
On the other extremity.
And.... Wear it!