I have seen many methods for assembling Katrina's soaker covers.
These are my favorite ways to do them.
Cut out your polyester fleece or your wool to the pattern templates.
**You can keep the waist band in one long piece, or you can cut the waist band in half length-wise and sew in to the front and back separately.
For very thin wool, I do 2 full body layers rather than the wetzone contour.
Pin your wet-zone layer onto your body layer.
Zig-zag stitch around the edge of the wet-zone layer fabric.
Now, with the outside up, place your folded leg fabric folded (where the leg holes will be.)
You can now either serge or zig-zag stitch it to the body. Pull only the leg cuff piece as you sew.
Repeat on the other side.
Fold the front up to the back. Inside facing outward. Pin or clip the sides.
Serge or zig-zag the sides together.
Now fold and sew or serge your waistband.
Fold down so the seams are hidden inside.
I like to roughly align my seam with the middle of the back.
Serge or zig-zag the waistband to the body.
OR, do the waist band in two segments:
Now just serge or zig-zag it all the way up the sides.
A yarn needle is your friend for dealing with serger tails!