Once you have created a full hexagram, look it up in the book. There will be two entries for each hexagram: Theme and Legend. Ignore the Legend when casting your character’s hexagram– the Theme suggests the issues going on in your character’s life, and the lessons it is endeavoring to learn.
Finally, as a group, you cast one final hexagram. This is the hexagram which rules the adventure; the passage that correlates will determine the overall themes the adventure should address. Using these, brainstorm and decide what the issue is that you’re setting off on an adventure in regards to: perhaps the children of your village are ill with a mysterious illness, or holy men are being systematically killed in supernatural ways, or the moon is slowly turning red.
But there’s more to your adventure hexagram than simply themes. In any good story, there is a Key and a Foil; the Key is the thing which solves the adventure, and the Foil is the thing which thwarts the solution. Every line of the adventure hexagram holds clues to the identities of both the Key and the Foil.
As an example, let’s say your adventure hexagram is #50, The Cauldron:
The Theme of the adventure would be as follows. (This is also what the meaning of your character hexagram would look like.)
You will have great success, which shall lead to envy from those around you; you will be confronted with problems which are beyond your ability. Your loftiest ideas will be impractical, and you seek responsibility you are not ready for. When you seek truth and responsibility with sincerity and admit what you do not know, wisdom will be yours for the taking. Others will help you, but only when you are receptive to them.
The Legend of the story– the clues to finding the Key and thwarting the Foil– would be as follows:
Iron legs hold the vessel above the fire.
When the vessel is full, the wife becomes ill.
There is a broken vessel in the rain:
When the legs are broken, the vessel spills.
One vessel hangs on a gold pole
One vessel hangs on a jade pole.
It is up to the GM to provide more information about the Legend during the game itself, but that is the all the information the characters begin with.