I would recommend getting a pair of 4 mm needles and a ball of Stylecraft Special DK wool. 4mm is a common size and Stylecraft special doesn't fray or split, is cheap and doesn't stick or squeak on your needles. Plus you can wash what you make without it shrinking or felting.
With regard needles, go for metal if you don't mind the click clack knitting noise or decent wood ones, not super cheap B&M or pound shop ones because they'll split or bend too much. Plastic ones can be a bit sticky and make it difficult to knit smoothly. I really like KnitPro Symfonie needles, they are smooth, good and pointy, strong so they don't feel like they're bending and they're really pretty.
A good way to learn is to pick up a knitting magazine like Simply knitting, they always have a mix of beginner and advanced patters, they always have a few pages towards the back devoted to step by step guides on how to knit and showing a variety of common stitches and they always have a jargon buster/abbreviations section that helps de-code the patterns.
Other than that, start by just doing a long swatch, a row of knit, a row of purl, a row of knit, a row of purl. Keep going till you realise you've stopped walking yourself through the steps of ' insert needle, wrap wool round....' then keep going for a bit longer, you want to build muscle memory.
By doing this you will have learnt how to cast on, knit, purl and cast off.
Once you can do knit stitch and purl stitch you can knit anything, because it's all just a combination of those 2 stitches.
- Garter stitch - just use the knit stitch for every row
- Stockinette - row of knit, row of purl
- Rib - cast on an even number of stitches, alternate Knit and Purl on the same row
Row 1 - K, P, K, P, K, P
Row 2 - K, P, K, P, K, P
gives you a fine rib stitch
Row 1 - K, K, K, P, P, P, K, K, K, P, P, P
Row 2 - K, K, K, P, P, P, K, K, K, P, P, P
Gives you wider ribs