Head downwind and move the back hand forward on the boom.
Let go of the front hand and stretch it out. Sorry I am a little out of the frame here.
As the board reaches the bottom of the arc then grab the boom again.
Keep the rig drawn back toward the tail and your body over the sail.
Place the forward foot in front of the mast and backwind the sail.
Push with your front foot, pull the mast vertical.