cb27.https://www.youtube.com/watch?v=l5-W21_SasA
Im not trying to be rude when I say this, but don't listen to that video.
Flatspins are really easy and fun and they are one of the first tricks I learned. What I came to figure out with them is that honestly the easiest way to do them is to think of it like a backflip with a Japan grab. You gotta get a nice solid pop and then going for the grab will help throw you into the flat rotation. Then start getting them more and more flat. PM me if you've got anymore questions