Mind the gap between the bottom of the bowl and the hook—about 2 inches is perfect. This way, the paddle will move properly and help form a good gluten structure.
If needed, turn the screw slightly counterclockwise (left) to raise the flat beater or clockwise (right) to lower it.
Your mixer is adjusted at the factory so that the flat beater just clears the bottom of the bowl. If the flat beater hits the bottom of the bowl or is too far from it, the clearance can be corrected as follows: