Make sure you set your altitude and compass before you take off, best done while the engine is warming up..
Use the 'course setter' plus or minus, to rotate the compass so that 'North' is lined up with the white line with the bar across it.. (on British Aircraft).
Then read the actual heading at the top of the compass to see which direction your aircraft is pointing too.. read off the heading, and then adjust your Directional Gyro compass to read the same..
Thats it, you are ready to go!
See this..
http://simhq.com/forum/ubbthreads.ph...e_compass.html