In the OSBot client, go to Advanced Settings and turn on Positions.
For getting an area use this:
Go to lowest Y and X co-ordinate (write it down).
Go to highest Y and X co-ordinate (write it down).
Then put it like this in the code:
private Area (NAME) = new Area(highestX, highestY, lowestX, lowestY);
That will give the rectangular area.