I don't know better for now than show you the links to the online manual to start with them:

http://www.conitec.net/beta/aentity-event.htm

http://www.conitec.net/beta/aent-scan_entity.htm

Try to build simple functions build on that. It is quite complicated.

Probably, in some issues of the AUM Magazine are articles about that, but I don't know where.

http://www.puppenheim.org/
http://www.wuerfels-welt.de
Old Game Tutorial: http://www.puppenheim.org/MITutorial.zip
Free Game Editor: http://puppenheim.org/AlienalsWeihnachtsmann.zip
http://www.puppenheim.org/blender_starting_main_settings.txt