this is it. The gm's will usually start showing up 30-60 minutes early & start seting up (event dependent of course) Show up 30-60 min early & ask the organizer (ie guy at counter at flgs, whoever unlocked the door, etc)who to talk to because you are new players.
My AL experience is at 'Cons. I usually come alone. I tell the organizer that I can be added to any short-handed group. I may not have a table until the last minute (with several other solo individuals), but I have never been turned away.
For a group: show up early, check in with the organizer, tell him/her you want to sit at a table together. A group of three can usually be used as the nucleus for a full table. Be ready to invite a pair or another trio of attendees to join you, to make a full table.
Last con it was my father, brother, son, and myself all trying to get at the same table. We has tickets for the game but there was a couple tables running the same game at the same time, but we were early and all got to sit together.
At the table my father and I need to flank the DM so we can hear what is being said, especially in a crowded room.