Carve upwind as you do for every normal tack. Push the windward rail and lean the rig back. (1)
… your feet to the new side. Bring the rig around by turning your whole body. (5)
Move your front foot in front of the mast to stabilize the board during the sail flip. (6)
Let go with your back hand soon enough! This way, the sail can rotate freely and doesn’t push you out of balance. (7)
Grab the boom and get ready to sail away
in the new direction. (8)
» Keep your front arm extended as long as backwinded.
» Control the sail power with your rear hand:
push to sheet-in | to sheet-out pull respectively give-in
The more experience you have doing this trick and when the sail shift is no problem anymore, you should try to do to the whole move flying on the foil.