The analogy of an author writing a play may help us to grasp how both aspects can be true. In the Shakespearean play Macbeth, the character Macbeth murders King Duncan. Now (if we assume for a moment that this is a fictional account), the question may be asked, "Who killed King Duncan?" On one level, the correct answer is "Macbeth." Within the context of the play he carried out the murder and is rightly to blame for it. But on another level, a correct answer to the question, "Who killed King Duncan?" would be "William Shakespeare": he wrote the play, he created all the characters in it, and he wrote the part where Macbeth killed King Duncan.
It would not be correct to say that because Macbeth killed King Duncan, William Shakespeare did not kill him. Nor would it be correct to say that because William Shakespeare killed King Duncan, Macbeth did not kill him. Both are true. On the level of the characters of the play Macbeth fully (100 percent) caused King Duncan's death, but on the level of the creator of the play, William Shakespeare fully (100 percent) caused king Duncan's death. In similiar fashion, we can understand that God fully causes thing in one way (as Creator), and we fully cause things in another way (as creatures).
pgs. 321 & 322
The words of King David himself mirror the above analogy:
All the days ordained for me were written in your book before one of them came to be. Psalm 139:16 NIV
Thus, it would seem that the world is God's storybook.