For the tech tree stuff, basically, the research is considered a unit, and when you build it, it triggers a couple different scripts that lock the research and unlock the unit.
Yeah. Bob is right. It's a bit confusing though.
For example, this is the code to unlock the Acclamator in Level 1 Empire (in Tech_Tree_Empire.xml)
find the following code tags
<Event Name="Start_Tech_1"> <Event_Type>STORY_TRIGGER</Event_Type> <Prereq>Tech_1_Freeze</Prereq> <Branch>Tech_Level</Branch> </Event>
then add the following lines
<Event Name="Activate_Acclamator_I-class_Assault_Ship"> <Event_Type>STORY_TRIGGER</Event_Type> <Reward_Type>TRIGGER_EVENT</Reward_Type> <Reward_Param1>Unlock_Acclamator_I-class_Assault_Ship_Research</Reward_Param1> <Prereq>Start_Tech_1</Prereq> <Branch>Tech_Level</Branch> </Event> <Event Name="Lock_Acclamator_I-class_Assault_Ship_Research"> <Event_Type>STORY_TRIGGER</Event_Type> <Reward_Type>LOCK_UNIT</Reward_Type> <Reward_Param1>E_Acclamator_I-class_Assault_Ship_Research</Reward_Param1> <Prereq>Activate_Acclamator_I-class_Assault_Ship</Prereq> <Branch>Tech_Level</Branch> </Event> <Event Name="Build_Acclamator_I-class_Assault_Ship_Research"> <Event_Type>STORY_TRIGGER</Event_Type> <Reward_Type>TRIGGER_EVENT</Reward_Type> <Reward_Param1>Research_Acclamator_I-class_Assault_Ship</Reward_Param1> <Prereq>Lock_Acclamator_I-class_Assault_Ship_Research</Prereq> <Branch>Tech_Level</Branch> </Event>
And don't forget to add this bit at the end along with all the other Tech 1 units.
<Event Name="End_Tech_1"> <Event_Type>STORY_TRIGGER</Event_Type> <Prereq> Build_Acclamator_I-class_Assault_Ship_Research, Build_Action_IV_Transport_Research, Build_Carrack-class_Light_Cruiser_Research, Build_CT-11_Space_Tug_Research, E_Build_Dreadnaught-class_Heavy_Cruiser_Research, Build_GAT-12g_Skipray_Blastboat_Research, Build_IPV-1_System_Patrol_Craft_Research, Build_Lambda-class_T-4_Shuttle_Research, Build_TIE_Starfighter_Research </Prereq> <Branch>Tech_Level</Branch> </Event>
Happy coding!
Ghost