I’m not 100% how Jade Empire works but with kotor we have a few ways a script can be executed.
These include dialogue (as DarthParametric advised), triggers that the player can walk into, actions with objects/npcs such as on death, on spawn etc.
I suppose it makes sense to know exactly *how* & *when* you want it to execute, do you just want it to be something that executes randomly after an event or during a specific event?