Yeah it was bit confusing, but you can get the general idea pretty easily if you at least start at the beginning of a series (The Lightning Thief, The Red Pyramid, The Lost Hero, The Sword Of Summer, or The Hidden Oracle)
A friend of mine told me to read it- a lot. So one day, I was bored so I checked it out from the schools library. And here I am. So first book was the Lightning Thief.