First, start with naked baby in need of a diaper.
I like to fold the back part under and lay her on top. That "lip" of diaper keeps the poo-splosions from going up the back.
The I roll each side in like so...
And so
Take the rolled parts up between the legs
And then fan them out to each side
Grab the corners of diaper from behind
And fasten!
Cover, and you're done!