1. Pin the right sides together and let one short side open
2. Sew three sides together and let one short side open
3. Pull the bag as its sides and sew across the edges (so you can cut away approx. 3cm from the corner on each side)
4. Turn inside out
5. Use pinking shears to cut out the open side (I could'nt finde mine so I used a scissor)
More photos soon...