Hey Sam, no worries about attending alone. Just be friendly and introduce yourself to people and you'll only be alone for as long as it takes to check in to the hotel. AT4 was my first GABIT convention (only my 2nd ever of any kind) and I'd made some friends on the Sanctuary message boards but otherwise didn't know anyone besides my mom (she'd come for the general touristing and reluctantly agreed to attend the convention as well, then became a fan of conventions by the end of the weekend). As we arrived at the hotel, I pointed to a group of women and announced that they were part of the convention. My mom asked how I knew because none of them were wearing convention badges yet and the convention t-shirts (a.k.a. convention uniform) hadn't been distributed. I answered, "It's a group of more than ten extremely excited females. And I could hear them from outside." I was completely right, of course.
The other convention attendees will not be hard to spot. Just look for the loud ones who can't quit grinning and periodically bounce off the walls. Join any group that's speaking a language you understand. If you don't immediately hit it off with them, join a bigger group. You'll quickly find someone to hang out with for the weekend.
As far as itinerary, last time the registration was on Friday afternoon, the meet & greet for the newbies to introduce themselves to each other was late on Friday afternoon, the opening ceremonies and Q&As started on Saturday, the charity auction and dance were Saturday evening, the serious crying took place on Sunday, and closing ceremonies was Sunday evening. The crying continued a little on Monday as people were saying goodbye in the lobby and making last-minute exchanges of email addresses. Pretty much everyone except for the last of us stragglers was gone by Tuesday morning. Don't skip anything if you can at all avoid it. Attend the auction even if you can't bid on anything because it's seriously quality entertainment, and the dance is fun if you're willing to ask to be taught the dances. Don't feel at all bad if you don't know them already, they're called condances for a reason. You won't have seen them outside of conventions. Oh, and there are YouTube videos for the well-known ones like
"Doctorin' the TARDIS" and "Star Trekking" (
comic rendition,
lyrics - That one's hard to find a good-quality instructional video for). In-person instruction is better, but if you'd like to take a look beforehand, there you go.