The 5 steps of the system are

1. Prepare,
2. Preview.
3. PhotoRead
4. Postview
5. Activate

The PhotoReading step is not searching, nothing is consciously read during that step. You're letting your mind take in the information for the preconscious processor to handle.
I know you might not understand what I just wrote, so, I suggest during the PhotoReading step, you turn the book upside down and flip the pages as fast as comfortable before your eyes. Say the chant to keep your focus directed at the book.

Activate in layers to build conscious comprehension,
Limit keywords to about 18. You won't need more during postviewing and form a question you want the author to answer for your purpose.

Alex