Uzuki is referring to the difference between Standard Type movement and Legacy Type movement.
In Standard, whenever you move "forward" or "back", the camera will snap behind you and your character model will maintain the direction you were facing.
In Legacy, "forward" will always move you away from the camera and "back" will move you toward the camera, regardless of what direction your model was facing a moment ago. Your camera will maintain its position. If you find the camera snapping behind you to be disorienting, this might be the setting you need.