First off, ignore analranger, or whatever "dsrertergr" is supposed to mean, they're just an angry asshat with no life skills, other than breathing air and occasionally sh!tting themselves...
Anyway, I know that setting the Target option in the GAttack makes the bombers unload at the waypoint with or without a human command.
For level bombing, make sure that you have an accurate lead-in and select an object with the Target Set in the Waypoint panel. Once that's set, go to the Target option in the Option panel and select Destroy Ground. After selecting the location to be "destroyed", click on the tab so you'll be able to select if it's a Primary or Secondary target, the radius of destruction and the percentage of destruction, etc...