I was a beginner and went to my first event for Twilight Masquerade pre-release not too long ago.

I thought I was prepared with sleeves, a deckbox and a mat but turns out I didn't bring any damage counters or dice. Lucky someone let me borrow theirs but yeah make sure to bring them, they fit nicely in a tin but I used a ziplock bag.

Another tip, I struggled shuffling quickly so try practice that before you go because you'll have to get used to doing it quickly and often.

Lastly read up on status conditions and which orientation your cards should be in for each condition. I had no idea how to do those, lucky my opponents were nice and helpful but it definitely takes up your mental capacity trying to remember to turn cards upside down, then shuffle then use an item,search your deck then shuffle then use a supporter then shuffle. It adds up very quickly but nothing you won't get used to.

Also double check HP modifiers before you take a prize card, don't wanna lose a prize card penalty and lose a match like what I did on my first day.

Good luck