If you just want to edit the Trainer data, you need to load your ROM in a Trainer editor (either the Trainer Editor in Kurapika's G3T, Unnamed Trainer Editor by Jambo51 or the somewhat outdated A-Trainer by HackMew) and go to the data with the name "Terry". There are going to be three Trainers, though, as the battles change depending on which starter you chose at the beginning of the game.
thanks i will find these tools very useful but what i wanna do is find the script that has the data so i can edit it!!
Open the champion room map in A-Map and check the header script.
where can i find header script for champion battle and oak speech?