Here are the steps to sew a French seam:
1. Place the wrong sides of the fabric together and pin in place.
2. Sew one stitch line the length of the fabric.
3. Press to set the stitches.
4. Trim the seam allowance down by several millimeters.
5. Turn the fabric pieces inwards so that right sides are facing each other.
6. Press along the stitched edge.
7. Sew the second line of stitches, enclosing the remainder of the seam allowance.
8. Press to finish the seam.
I hope this helps! Let me know if you have any other questions or if there's anything else I can help you with.
