For the CAR's, it is simply what you would normally do. Some areas of the country allows CAR to give offsides, free-kicks, etc; so I would expect a good briefing. In the other areas where it is simple ball in/out, there is not much to add other than "ask who is doing it, and say you want a clear flag".
For Team officials, it is to introduce yourself, get the team sheets and check the subs details. Also, if "repeat substitutions", then to wait for permission to make the change.