Hover over NED's components to gain a better understanding before you start poking and clicking. You'll notice the wind direction and the HDG (compass heading) have changed appropriately. With NED, for simulation purposes and to give you a feel that the boat is turning when you activate the helm button, the boat turns with the helm but it immediately flicks back up to it's normal proper position. On a real wind meter, the boat always faces up because you're always behind the meter. You'll notice that the red triangle represents the relative position of the wind to the boat.

The graphic below is representative of a real wind meter on a sailboat. Before you play with NED, read this first. NED teaches you how to set the sails for every wind angle.

NED is the world's best sailing simulator for teaching basic understanding of sail trim.