i've never really been to one before to be honest. i'm gonna mask up and dress plainly and all that. i still don't know what to expect or if there's any social protocols to be aware of while going to these. i'm autistic and very nervous please advise 
Don't go to the protest. Instead hang back and follow the fash back to their cars. Get pics and license plates.
This is extremely dangerous and not something you should be doing at your first protest, or alone. Leave this kind of thing for the experienced anti-fa. A newbie probably won't have any connections they can give the info too anyway.
Fair. There's always Unicorn Riot tho.
Unicorn Riot does good work.