In terms of paper, I use pre-hole-punched paper from this website. You can get a lot of other supplies from there, too.
You can really use any kind of paper though, but that stuff is strong, thin enough to see like 10 layers when you shine light through it, and it’s conveniently hole punched already for peg bars.
A quick google search will find you some basic tutorials, but most of the stuff you’ll find free online are based around Flash or Maya. To get you started on animating, you’ll really want to pick up "The Animator’s Survival Kit". It has all you need to know as a beginner, and many animation classes use that as the text book. Other good books to check out are “The Illusion of Life" (a combination history of Disney animation and the process in general) by Frank Thomas and Ollie Johnston and "Character Animation Crash Course!" by Eric Goldberg. Both of those have good foundational stuff as well.