Left handed ? sit facing a right handed knitter
and just copy.
Seriously it's how my Mum taught a neighbour to knit.
Failing an obliging neighbour, youTube's probably a good idea
First stuff ? knit string squares. They make great dish scrubbers and when they get too grubby, they're excellent for cleaning shoes and boots. It's just a square, it doesn't matter if it's not perfect, it gets you started, it's not a huge thing, it's practice, it lets you get to grips with the whole process of how and how tight and how to hold it all, without any stress.
If you take to it and keep knitting them in wool they make a warm blanket too.
Needles ? I tuck mine under my arm, so I prefer long, unless I'm doing rounds and then I use five pins. I loathe circular needles, but they seem to be very in just now.
Size wise, the standard for a beginner when I was little was an 8 which is pretty close to a modern 4. If you find old needles in a charity shop the 8 will be a skinny 4mm diameter.
That size or anything a little thicker will do fine. I don't think I'd advise a beginner to go anything above a modern 6mm pin.
Charity shop needles are often a very good buy. Often a good place to pick up wool too though.
Patterns are a personal choice, but Sally in Wales has a pattern for socks on Downsizer that is very, very good. Straightforward and well explained and illustrated.
Best of luck with it; it's an incredibly useful skill and worth a bit of effort.
atb,
M