Dave and the rest have it pretty well covered: build it inside out, saddle stitch it with waxed linen thread, use a welt about 3/8th inch wide to hide your stitches. Then turn it and trim the welt if it sticks out too far.
That's real nice leather, it has a pretty texture to it and it won't fight you much when you turn it, by the look of it.
Do a search here on saddle stitch if you don't know what we're babbling about.
Stitch on!
Moose