I-Ching

I recently discovered the I-Ching, but really I don't understand how to ask and how it works ... The I-Ching was mentioned in a post about Terence McKenna - where it was used to forecast the future.

The Book of Changes:

I've used it to develop the direction of a novel (please reserve your comments for Yandro, if you will). Jung used it with patients to get around their psychological blind spots. Leibnitz based his binary system on it, the open-and-shut-gate idea, if not his entire philosophy of monadology . . . for what that's worth.

Then I found this Philip K. Dick interview that gives some more clues