Instructions
Follow the "Event" markers on your in-game mini-map. All throughout the game these markers guide you to your next destination, and "Chapter 11" is no exception. Follow each marker from one part of the chapter to another, picking up the items and supplies you find along the way.
Activate the robot that you come across near the end of the chapter. The in-game event that triggers the fight with Barthandelus can't begin until the robot is activated. Walk up to it and interact with it using the "X" button. The robot will be activated, and a new event marker will appear on your mini-map.
Follow the path to the final mini-marker. Walk as far as you can along the path, until there is no place else to go. This will trigger the in-game event that allows you to detect Barthandelus. After a short cutscene, the fight will begin.