@ambyrb The best (and worst) part about tarot is that -- it is literally whatever you want it to be.
There are different spreads for different purposes and that will determine how many cards you draw and what their purpose is.
When I first started, I used this site for spreads:
http://psychiclibrary.com/beyondBooks/tarot-card-spreads/
however now, I just pull how many ever I need until I have a full picture/understanding.