Grab the mast below the boom and straighten it to get as much of the sail exposed to the wind, albeit just a few knots, as possible.
Now push the sail vertical and grab the sail foot as the sail goes vertical. Plant the feet around the mast base and bend at the waiste.
Grab lower on the mast as the sail starts to lean the other way.
As the sail leans away from you pull down into into the board and use your legs to stand up. You are using the sail as a counter balance to pull your weight down into the board instead of against the (would be) wind.
Grab higher on the mast and stand higher over the centerline of the board.
Now grab the boom with the back hand and lean the the mast forward into the wind.
Grab the boom with the other hand.