This picture shows where the fabric should be before you sew the sides.
Once you have ironed your fabrics, you are ready to sew them together.
Sew the hems first. When you iron, create a straight hem to start with and then fold that hem over about a cm to stop the fabric fraying. You will end up with a tube along the bottom. I then sewed a straight stitch along giving a neat finish. Sew the hems on both your lining & PF. You are then ready to pin your fabrics together.