How can we use Zend Framework Page Cache Version 1.12.3

I’m looking for proper way or documentation of using Zend Framework Page Cache. I know how to use the Core cache. But I want to cache the complete page and the documentation from Zend official site is not helping me anyhow.
I know how to set front end parameters what I need how to save the page.

//caching database result        
    $frontendOptions = array(
        'lifetime' => 600, // cache lifetime of 10 min
        'automatic_serialization' => true, 
        'debug_header' => true,
        'regexps' => array(
            '^/testController/testView/' => ['cache' => true],

        )
     );

     $backendOptions = array(

         'cache_dir' => '/tmp/' // Directory where to put the cache files

     );

     // getting a Zend_Cache_Page object
     $cache = Zend_Cache::factory('Page',
                                  'File',
                                  $frontendOptions,
                                  $backendOptions);

     if(!$cache->load("testCache")) {
         $cache -> save($page, "testCache");
     }

Am I saving the cache in right way?

If so where can I get the $page? I mean documentation show no way for saving the page.

But it gives these lines

$cache->start();
// if the cache is hit, the result is sent to the browser and the
// script stop here

// […] the end of the bootstrap file
// these lines won’t be executed if the cache is hit

NOTE: Im using Zend Framework Version 1.12.3