First of all get some books on leather work. The good new is that the expensive ones are still under $20. Next, I would get a good video on sheath building. I happen to have a like the one by Chuck Burrows. I'm sure that Boss Dog, aka Tracy, at USA Knife Maker Supply has both. Between the two you should find out all about leather and tools that you will need to know and watching how it's done is a lot easier to to follow than illustrations in a book. Making sheaths is like making knives in that you can make them fancy or you can make them utilitarian. I happen to get most of my tools from Eleather which, unless you want to get a sewing machine, don't cost a whole lot. Do get or make yourself a stitching pony. They are not very expensive and it will make the job of sewing a lot easier. That or learn to hold your work with your feet.:3: Chuck shows how to use one in his video.
Doug