First open up GM8
1)Open Flight engine.GMK
Go to Advanced Mode:
Create A new Script Called
"BulletEnemyCollision" (This is the common name for this kind of script)
Now Attach it to the Projectile Object
"ObjBullet"
Now we have created a Code which will make a projectile damage an enemy plane.
More tutorials to come - How to create object (bullet projectile)