Explanation of Cache Bins

I've enabled this module and added the suggested code from the documentation to my settings.php file. In my case:

$conf['cache_backends'] = array('sites/all/modules/apc/drupal_apc_cache.inc');
$conf['cache_default_class'] = 'DrupalAPCCache';

My status page says that APC is working fine. However, the status says: APC has been running for 44 min 54 sec. Currently caching 0 entries (0 bytes). When I read that I realized that probably nothing is getting cached.

I then came across some issues here where people mention "cache bins" like this one. However, there was nothing in the documentation about adding any of this additional code. Did I miss something or is this not really documented? If so, how do I know which bins to add? Thanks.