This is a variation of adding a pocket to the side of the skirt. Please see How to Add A Pocket for adding just a pocket.
Prepare the front and the back panels.
For both panels, there are “right” sides, or the side that are worn to be seen. The “wrong” sides are the side touching our skin.
Prepare the fabric for the pockets.
“Top Panel” refers to the panel touching the back of the hand when we put our hands inside the pocket. This can be the lining of the skirt.
“Bottom Panel” refers to the panel we touch with our palms. Use the same fabric as the front panel of the skirt when cutting the bottom pocket panel.
For the zipper, we will need an invisible zipper.
Make sure both pocket panels have the same curves as the skirl front and back panels.
Layout the zipper, the skirt “Back Panel”, and the pocket “Bottom Panel” to get an idea how each item is positioned to each other.
Sew the invisible zipper: one side to the “Back Panel” and the other to the “Bottom Panel”.
Take the pocket “Top Panel” and skirt “Front Panel”, right sides facing each other, and sew them together.
Pin the two pocket panels together, with right sides facing each other. Sew around the pockets.
For this part, I found it easier to hand stitch from the right side of the panels.
Line up the panels so that the right side of the two pocket panels are facing each other.
From the top to the first set of red pins, hand stitch the skirt “Front Panel” and pocket “Bottom Panel” together.
Do the same from the second set of red pins to the set of gold pins.
The gold pins are placed just right where the zipper stops. From the set of gold pins to the end of the skirt panels, sew the skirt “Front Panel” and “Back Panel” together.
Press the seams and the pocket is complete.