I agree with Stefan on most of it. Back in the first year I think I went to about 2/3 of the talks; the first intro one at the Great Hall back on the first day for all of County, the one for my course and maybe something else.
The first one wasn't really worth going to. We just sat in there and the dean (I think) introduced himself and the head of the JCR, along with a couple of other people. I don't really remember who they were or what it was about, but none of it was essential or anything, most of it was just common sense.
The course one was just introducing the head of the course and telling us to buy some book or something like that. I guess that one gives you an early chance to meet some people on your course, but again I don't reckon it was essential.
A couple of my flatmates went to some other chats which it said you had to go to (I think it was one about the bus service and one just on general safety/fire stuff), said they were pointless and didn't bother going to any others. They were early too, so ******** to getting out of bed hungover to hear someone go on about which bus to catch or telling you to stand outside your flat if the fire alarm goes off, that's common sense.
Just remember to go to your registration stuff and your set, and that stuff is a piece of piss. Fill out some forms and get them signed and read about which courses you want to do and get them signed by the head of the course, piece of piss.
Your man who said about the library card photo is bang on as well. When I went down there I didn't realise I was getting my pic taken and overslept so just rushed down there looking and feeling like ****. Didn't realise you're stuck with that picture for the whole time too, gutted.
But yeah, it's what you make it, just do what you want. You're gunna be living with flatmates for 30+ weeks so get to know them obviously. Just have a laugh, get your flatmates together and go knocking on other flats and get a party going or something. Booze is your friend, since chances are most people won't know each other and will be nervous/bricking it. Just get some drinks on the go and talk to people. Don't be the person who just stays in your room ignoring people. I had one of them in my flat last year and it was annoying as ****, he never stepped foot in the kitchen and nobody knew his name for the entire year. Just be sound and socialise with your flatmates. Don't have to be best mates or owt if you don't want to be, just don't be some shut in weirdo.