Tarot cards are normally a set of 72 cards carrying both Minor and Major Arcana. They show you want you wish to hear by using spreads. There are thousands of different spreads out there and you can even make some if you are that skilled.
Tarot cards shows you the way to the answer. They don't just give you the answer, they make you think about the issue therefore giving you some idea on how to handle it. They don't normally work will as future telling tools because the future is not set in stone.
You can use them to see how your day is going to turn out or/and make profit out of them. They are there to help people solve their issues or questions about themselves. Stuff like are they going to get that job, how is my boyfriend doing, is my mother going to be alright, I want to know a little bit about my past (This is hard because it is a cold reading), and stuff that is around them and their live. If they are asking about someone they have never meet like, How is Obama doing, than it won't work at all.
Hope this helped and I know it doesn't explain everything, if you have questions you can email me.