You really only need to worry about getting yourself to the right position at the right time. Let the officers and NCOs do the training. It is their job. Your job is to pay attention, and maybe you'll learn something too. Do not smoke in the ranks.
Smoking is unsafe around powder and it is against regulations.
At all times while in ranks, be quiet. Talking is permitted on the march, but do not make idle chatter. This happens all the time and there is no reason for it. Do not talk about the car trip to the reenactment, or your new hardcore shirt, reenacting politics, or the football game you are missing. Save modern conversations for modern times.