7. Place the strap that's been folded into half right in the middle where the mark is
8. Sew it in place
9. Place the zipper on the lining piece right in the middle of the longest length of the fabric
10. Lay the exterior fabric with strap sewn, on top of the zipper with right side of both fabrics facing together
11. Make sure that the zipper is unzipped
12. Start sewing from the middle and stop about an inch before the end of the fabric
13. Snip the zipper, cut the end of both fabric to make it into curve
14. Place the exterior fabric on top of the zipper again and continue sewing the curve right to the end of the fabric
15. This is how it looks like inside
16. Exterior view with one side of the zipper sewn
17. Repeat the same step for the other side with the zipper unzipped
That's it! It's done and ready for some show off :)
Alternative for the strap by using ribbon.
Good luck and Happy Sewing!