Welcome! I am still fairly new to all this too, just over a month ago I had nothing and now I have quite a bit and am using cloth full time – my poor Paypal account!
AIOs and pockets are the easiest (fitteds – which are the 2 part nappies that you need to put a wrap over the top – are also lovely but usually a bit bulkier) and I started off thinking that I’d just stick to them but no, I was tempted by lovely fitteds and wraps too. The slimmest/thinnest AIOs I have are Ittis! Also if you want to try pockets, Coolababys are a nice cheap one to start off with.
You will need a nappy bucket and a wetbag (I got my nappy bucket from Cheeks and Cherries but any bucket with a lid will do). Or some people just use a wetbag instead of a bucket.