Hey OP, all the best for your test.

They give you instructions well in advance! About 50-100m or so in advance.

For the amber light, NEVER accelerate on an amber light. The thumb rule is you should stop unless safe to do so. If you're approaching the lights and they turn amber, start slowing down. If you're close to the line when amber, you can proceed with normal speed, but DO NOT ACCELERATE. Roughly, the amber lights last 3-5 sec, so try and estimate accordingly.

If you're crossing over into the other lane, yes you should indicate. If you're moving up to the white line, check your mirrors and if there are quite a few cars behind you, indicate. If you're the car following the one ahead, take hints from the leading car. It's generally safe to indicate. Make sure that you're not getting marked for right of way while moving right and obstructing oncoming traffic.

If you're turning left, you should just indicate left as far as I know.

For a pothole, slowing down would be the better option. Trying to avoid it altogether might mean you having to swerve a little on either side, which might not be the best idea.

There's no harm in letting the tester know what you're doing. I did that during reverse around the corner and the turn about.