No need to run out and buy leather - recycled leather will do the job. Cut up an old bag or find something at the thrift store. Don't get carried away with the zipper - this project can come together quickly, even if you're new to sewing.
Cut about 30" of thread and insert one end through the eye of the needle. Pull so both ends are even and knot the end.
Place the zipper in the center of one of the 10” sides of the leather. The top side of the zipper and the pretty side of the leather should face each other.
Start sewing the zipper to the leather. Insert the needle into the wrong side of the skin, about 1/4” from the end of the zipper (unzip it if it makes sewing easier). Make a simple straight stitch across the zipper, near the teeth. Don't worry if your points aren't perfect.
When you get to the end, tie a knot about 1/4” on the outside of the other end of the zipper. Insert the needle through some of the zipper fabric and pull the thread until a small loop remains; then insert the needle through that little loop and pull. This makes a firm knot; repeat a couple more times.
Attach the zipper to the other end of the leather in the same way, and then sew it on.
Thread the needle again, and at one end of the zipper, bring the two sides of the zipper fabric together with a few stitches, about 1/2" from the end of the metal teeth.
On each side of the zipper, draw a straight line on the back of the leather, starting about 1/2" outside the ends of the metal zipper teeth.
Using the same thread, start sewing the side of the bag, following the drawn line. The first few stitches can be difficult because you are sewing multiple layers of leather; use the thimble to push the needle through if necessary.
When you get to the end, tie a knot in the thread the same way you did before.
Repeat the process on the other side.
On each side of the zipper, draw a straight line on the back of the leather, starting about 1/2" outside the ends of the metal zipper teeth.
Using the same thread, start sewing the side of the bag, following the drawn line. The first few stitches can be difficult because you are sewing multiple layers of leather; use the thimble to push the needle through if necessary. When you get to the end, tie a knot in the thread the same way you did before.
Repeat the process on the other side.
When both edges are sewn, trim off the excess leather. Leave about 1/2” on each side. Then trim the corners at an angle, being careful not to get too close to the thread.
Turn the bag clockwise through the zipper hole and lay the corners flat.
