Step 6: Flying the kite with help.
Hand your kite to your friend, and send them ten metres down-wind.
Your friend faces you, and holds the kite above their head. They do not throw the kite into the air.
Apply a little tension to the line, then shout "let go!" to your friend. They do not throw the kite into the air, but merely let go, take a step backwards, and leave it to climb by itself. You can then unwind more thread as you wish.
For a more detailed description of launching, alone or with help, please check my earlier Instructable.
For a more in-depth discussion of kite safety, please read this other step from the same Instructable.