I found instructions on how to make one:::
Made a rectangle pattern -- 9" x 30"
Make another rectangle pattern for pockets 9" x 6" - cut 4 sets (double - right sides together)
Put right sides together and cut one out double for front/back.
Cut a piece of felt that is 1" shorter than the pattern -- this will be your interfacing.
Cut out 4 pockets (doubled)
With right sides together, stitch top and bottom of each pocket. Turn and press flat.
Baste the felt to the wrong side of one of the pattern pieces.
Pin pockets to front of FE that you just basted, matching edges.
Baste pockets along the sides.
Sew bottom of each pocket to the front of FE. I used a decorative stitch. You could also use some type of ribbon or bias tape.
Pin back of fish extender to front with right sides together.
Stitch using 3/8" seam allowance leaving about a 3 to 4 inch section unstitched to turn the FE right side out.
Trim corners and turn right side out.
Iron flat and stitch the unstitched section closed.
At the top of the FE, turn down to make a casing to put a wooden dowel rod.
Decorate your pockets . . . depending on how you're going to decorate your pockets . . . either decorate them before you baste them to the front of the FE or after the FE is totally sewn.
Excuse my half-sewing/half-made up verbage.
Hope this helps a little.