I'm experimenting with 3rd Edition and 4th Edition approaches..."Old vs New", so to speak.

(I only have the 3rd Edition).
From what I gather, the changes look like this. (Correct me if I'm wrong).
3rd Edition (2000)
(a) Prepare
(b) Preview (Survey, Trigger words)
(c) Photoread
(d) Activate
(e) Rapid Read (Optional)
4th Edition (2007)
(a) Prepare
(b) Preview (90 sec)
(c) Photoread
(d) Postview (Survey, Trigger words, Mind Probe questions)
(e) Activate (includes Rapid Read now)
For both Editions, Prepare and Photoread remain unchanged.
The Preview step has been changed, according to Alex's posts around the web, its now 90 sec.
This may sound a bit stupid, but since Postview now has "Survey" and "Trigger words", what is Preview for?

I'm not sure what am I supposed to be doing for the 90 seconds in the Preview step.

Can anyone clarify? Thanks.