Once you free the sail, push the mast hand up high and grab the boom with the rear hand. If you’re gasping at this point, take a moment to steady yourself, breath….then drop the mast hand down on to the boom.
To control the rig and position the board, ‘fan’ the clew/backhand in and out to control and exhaust the rigs power. If you hold the rig still, the sail powers up and it’s harder to steer as the board sails away from you.
Use the front arm to control the height of the rig = Lower in strong winds and higher in lighter winds. Keeping your feet straight down helps you to control and ‘fan’ the rig.
To steer, use exactly the same skills as a beach start or normal steering, twist the rig forward to bear away, rake it towards the tail to head upwind. You want to end up with the body near the tail and the rig well clear of the water.