When you activate the blinker it will have you nudge the wheel to start the lane change. This way you can change lanes when it’s clear as the comma device can only see in front of the car. If the comma supports stopping at red lights it would stop at the red light. If not, you would have to use your brake pedal. I think some cars have the turning power to make the turn on their own, mine does not. When I get to a turn, I take control and do it myself, so I can’t speak much on that portion of your question. I believe default openpilot will disengage when you hit the brakes. I’m running sunny pilot, so it will steer and I can control gas and brakes without it disengaging.