i guess ill say stuff from my own knowledge and from what others have told me:
bend your knees, and jump high
throw your feet out to the sides and bring your hand down to the deck, hit it just a little bit
get that hand back on the bar AS FAST AS YOU CAN and then use your wrists to help the scooter finish the rotation
once rotation finishes get your feet back on and ride away clean.
caution : takes practice. For me: took about 1 week of nonstop practice with the trick and about 2 or 3 months of just like kinda wanting to do it but not setting my mind on doing it.