Two pieces for the outer layer and two for the lining (typically cm for a small pouch).
For a visual walkthrough on assembling a similar zippered tote or pouch, you can follow this detailed sewing tutorial: Adriana Rioszip
Iron the interfacing onto the wrong side of your outer fabric pieces. Two pieces for the outer layer and two
Open the zipper halfway (crucial for turning!). Pin the outer pieces together and the lining pieces together. Sew all the way around, leaving a small opening in the lining. Adriana Rioszip
Sandwich the zipper between the outer fabric (face down) and the lining fabric (face up). The zipper teeth should be facing the outer fabric.