For queue monitoring to work you need to have a provider plugin installed - check out the details for you provider to see if its available. You must ensure that the plugin is explicitly configured in the session configuration as in this example. To configure right click on a session (to add all queues) or on a single queue and select Watch which allows you to add to an existing or create a new watch frame.
You must explicity right click in the watch panel and select save to keep your configuration. Options (such as polling frequency) can be set in the "Preferences->General" dialog.
Hermes collects the queue depth, the age of the oldest message and some provider specific statistics - if you want to view the provider specifics the drill down in the hierarchical table as this following example shows. The frame can be floated outside of the main Hermes window or docked anywhere inside it.