There’s some good stuff out there, but most people are sick of answering two threads like this a week.
I suggest Mark’s unispin video tutorial and Shaun’s video crankflip tutorial, both on Youtube. unispin crankflip
when you go to flip the cranks kick your forward foot outward as if you were flipping a skateboard, this is the one thing that isn’t clear in the tutorial
plastic pedals help with both, if you use metal pedals wear shinguards