First find the magnetic deviation or declination for your area using an aviation map, Google, trial and error, or use the Calibrate button under the adjust menu. After you save that, you lay your phone flat to get a compass reading which is displayed at the bottom of the screen. Notice the reading, then move your device in a figure 8 pattern and then look at the reading. You just calibrated the compass. I've seen readings off more than 25 degress, when I've forgotten to reset the compass. Wuts @ Free is only as accurate as the GPS and compass informaiton. Now point your phone to an interesting object. It may be a building, a mountain top, a fire, etc. Hit A. It will save the coordinates until you move loactions to a different angle. You can even end the application or shut off the phone. Your A coordinate is set. Once you get to whatever your B location is, calibrate the compass again, point the phone and hit B. At this point a Google map will come up showing a map of what you pointed to. If you hit the back arrow, you can see the exact coorinates of C that the program calculated.