sounds like a decent tourney for popping your cherry! It will get better and easier with experience.
All in all, it is not that different than online except only playing 1 table at a time.
The only other considerations are dealing with chips and showdowns....things like "players throwing out 1 single oversized chip is just a call" you only have to make that mistake once.
other little chip things you'll pick up like being able to quickly size up an opponent's stack, that is pretty helpful.
Also with showdowns, you want to make sure to make your opponents show when they are supposed to, and you want to avoid showing when you don't have to. This is something that the software automatically handles for you. Sometimes I still mess this up when I find myself in a huge pot and I'm just so excited to have the hand be over with what I think is the winning hand, that I just table my hand and they muck. Dangit! Or worse, I table my hand out of turn, they show me a hand that beats me and now the whole entire table got to see how I was outplayed.
Go ahead and wear the sunglasses and hoodie or hat. I don't always wear sunglasses anymore but I always used to and it made me feel more comfy. Anything to make you feel like you are comfortable is a good thing.
Also, try not to check your hand until it is your action. This will accomplish 3 important things:
#1 Nobody can get a read on your hand strength if you haven't looked yet.
#2 You can be watching other players to try and get a read on their hand strength
#3 it keeps you much more focused on the developing action if you don't already know you are going to fold that 7-deuce...helps you keep your head in the game so to speak.
Since I'm not that great yet at picking up physical tells
I am mostly concerned with not giving them off.
Post flop, don't look at the flop as the dealer lays it down, instead look at your opponent. Eventually you will be looking at their reaction to the flop, but for now you are just trying to not let them see your reaction.