Drag the points of the survey area to move them around, drag the markers in the center of the sides to add a new point.
Right click on a point to delete it.
Drag the survey area itself to move it as a whole.

"Fit view to area" will move the map view to be centered on the survey area location.
"Fit area to view" will move the survey area to the current location of the map.
You can copy and paste the coordinates list from the text area, eg. to save them in a text file for use later.
Pasting coordinates into the text area will update the survey area from the pasted points.

• Entry angle: angle in degrees (0=north,increasing clockwise) of first row heading
• First turn: direction to turn at the end of the first row
• Row separation: distance between rows in meters
• Altitude: desired altitude of flight (all waypoints will be the same)
• Flight speed: set a speed to use in time estimate calculation
• Turn time: set the approximate time taken for the UAV to turn at each waypoint, for a more accurate estimate

"Efficiency" is the time spent moving along a row, as a percentage of the overall flight time.

See this YouTube video for a demo.