format book layout in Page 5.6.2??

You don't/can't.

Use Pages '09.

Besides the lack of facing pages there is an enormously long list of other missing features in Pages 5 and a basic problem of the color space sticking in RGB.

Not to mention the good chance you might lose it all and not be able to recover any of it.

Peter

So how can I get back to an earlier version of Pages where you could have facing pages?

You buy the retail box of iWork '09 from a third party such as Amazon.com or eBay. Be sure to run Software Update after installing & before running any of the applications. You can download the standalone updater from this page.

If you had Pages '09 before you should still have it in your Applications/iWork '09 folder.

Peter