The power is lowest at the sides of the wind window so launch and land your kite there.
Here is another diagram that shows the Power Zone and the 12 o’clock zenith position. Avoid rapidly moving your kite through the center power zone section (ie from the 3 o’clock to 12 or 11 o’clock position). Doing this will cause the pulling force will be too great and you will get launched downwind.
The least wind is at the edges of the wind window. The “power zone” is in the middle. When first flying your kiteboarding practice kite or trainer you want to avoid flying it into the power zone until you feel comfortable with the kite’s control. When flying the practice kite into the power zone prepare for some pull on the handle and don’t let it pull out of your hand. When you master flying the kiteboarding practice kite or trainer, try flying the kite while standing on a landboard. Dip the kite down into the power zone to get some pull. Bend your knees and brace yourself on the board. You will begin to move forward. Keep dipping the kite into the power zone. The faster you keep dipping the kite the more power you will get. Once you get the hang of going straight down wind with your practice kite begin to carve perpendicular to the wind on the landboard. Keep practicing this with your kiteboarding trainer kite and you will be ready for the water in no time!