All hand signals should be made with the left arm, from the driver's side of the bucket.

To indicate that you intend to turn right, extend your left forearm and hand upwards with the palm of the hand facing forwards.

To indicate that you intend to turn left, extend your left forearm and hand leftwards with the palm of the hand facing forwards.

And instead of brake lights

To indicate that you intend to slow down or stop, extend your left forearm and hand downwards with the palm of the hand facing backwards.