You need a deck for starters, then you would most likely need a tarot book that explains the cards. The deck is seperated by the Major and Minor Arcana, the Minor Arcana contains almost a normal deck of cards except it doesn't use hearts, diamonds, etc. it uses pentacles, wands, etc.
The readings are based off of knowledge of the deck, the person you're reading for, and general intuition. I would say most of the reading is based off of intuition.
When doing tarot you use certain spreads, or arrangements of the cards, to help you in your reading. Each spread has a different meaning for each place where the cards are. There are many different types of spreads, and certain spreads work better with certain themes. If you're doing a love reading for someone, it's usually best to find a spread that fits that theme.
This is just the tip of the iceberg, but now you know a little about tarot.