The sample I did was the AIO sewn-in soaker version. My layers are microfleece stay-dry top, then two layers of cotton fleece, and then heavy bamboo fleece on the bottom.
First, serge around your flap-style soaker.
Pin your soaker to your anti-pill fleece inner.
Use a zig-zag stitch to sew down the top end and keep it flush.
Then, serge around the body of the diaper keeping the front open.
View from the top PUL fabric side:
Add your elastic casing channels and install your elastic.
Serge closed the front of the diaper, and add your wing snaps and top umbilical snap.
Templates can be downloaded here: http://prefold2fitted.blogspot.com/2012/10/online-free-downloads.html