If you followed the Setup you will have a bunch of services registered. For the Basic-Usage you only need the Client to execute all the Actions the Client has implemented.
# AcmeBundle/IndexController.php
public function messageAction()
{
$client = $this->get('dz.slack.client');
$response = $client->send(
\DZunke\SlackBundle\Slack\Client\Actions::ACTION_POST_MESSAGE,
[
'identity' => $this->get('dz.slack.identity_bag')->get('CoffeeBrewer'),
'channel' => '#slack-testing',
'text' => 'Good Morning, please make sure u got a coffee before working!'
]
);
}