I look at it this way - if there's ever been a situation where you, as an AR, weren't sure what the referee expected of you (or an area where you know different referees expect different things) then cover it in your prematch. In a nutshell, I would cover (in no particular order)...
pre-kickoff - after coin toss check nets
Penalty kick - FK right on edge, run to goal line if PK, not if DFK. What signal I want for a PK I've missed (2 scenarios - something I've completely and utterly missed, or when you think I might have a view but I'm looking to you for help)
Fouls - look for eye contact, close it is to them more I rely on them, especially if it looks like they have a better view. If it's in the middle of the park and you can see me looking across, then I'm looking for help. Especially things like shirt pulling where it's easy for me to be blindsided
offside - wait and see, early flag if 50-50 with keeper
Match record - Record everything, but there should never be 3 of us with our heads down. Far AR to record first as much as possible.
Apologise in advance if I ever overrule - it's just because I think I had a better view. If I screwed it up I'm the one who wears it anyway
Throw-ins, CK/GK - eye contact first, flag down on the side you want to signal (especially if you have a few moments as the ball approaches the line), that tells me what you think it is and I know to signal first if I'm going to disagree, and mirror my signal.
Managing subs - try to get the player ready to go first, go to halfway, I'll wait for you to be back in position
Dissent - call me over if it needs a card or if the bench is starting to cross the line
mass confrontation - AR1 to manage the benches, ARs to come onto the field if needed, I'll need them to tell me who did what because I have a bad habit of getting stuck in the middle
Off-the-ball play - you guys are the eyes in the back of my head. Keep an eye on potential situations or late tackles
Manage players as much as you can, let me know if somebody needs a card
Run to me at halftime to meet in the middle
Both AR's to bring full referees kit out (cards, whistle, etc)
Have fun!
I might modify certain aspects a bit if I know it's a particularly inexperienced AR, just judge it on how they're feeling about their confidence and capability. If I'm doing a warmup, then my ARs are going to join me and I'll just cover the prematch while stretching. I'll preface it by stating it's all the usual stuff
It's a lot, but it's not that unusual in my area. When if refereed in my old area where most refs don't even do a prematch I'd cut it down a bit. When in Rome, etc.