Once you have downloaded outline files from any source or have a outline file you have created:
1.) Go to your RadarBox 2008 folder (Normally C:\Program Files\AirNav Systems\AirNav RadarBox 2008)
2.) Create a new folder called "Outlines"
3.) Open that folder and place your outlines files in there
4.) Close RadarBox 2008 if its open and start RadarBox 2008 again
The outlines will now be displayed on your map. If they do not appear go to the Menu Map and click Outlines.
To hide the Outline, go the Menu Map and untick Outlines or delete the specific outline file from the Outlines folder.